chore: cherry pick git executor revert (#39954)

## Description
- Git executor CE Impl revert PR
#39949


Fixes #`Issue Number`  
_or_  
Fixes `Issue URL`
> [!WARNING]  
> _If no issue exists, please create an issue first, and check with the
maintainers if the issue is valid._

## Automation

/ok-to-test tags="@tag.Git"

### 🔍 Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!CAUTION]
> 🔴 🔴 🔴 Some tests have failed.
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/14106311517>
> Commit: cef9ab7
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=14106311517&attempt=2&selectiontype=test&testsstatus=failed&specsstatus=fail"
target="_blank">Cypress dashboard</a>.
> Tags: @tag.Git
> Spec: 
> The following are new failures, please fix them before merging the PR:
<ol>
> <li>cypress/e2e/Regression/Apps/ImportExportForkApplication_spec.js
> <li>cypress/e2e/Regression/ClientSide/BugTests/CatchBlock_Spec.ts
> <li>cypress/e2e/Regression/ClientSide/BugTests/DS_Bug28985_spec.ts
>
<li>cypress/e2e/Regression/ClientSide/BugTests/GraphQL_Binding_Bug16702_Spec.ts
> <li>cypress/e2e/Regression/ClientSide/Git/GitAutocommit_spec.ts
>
<li>cypress/e2e/Regression/ClientSide/Git/GitDiscardChange/DiscardChanges_spec.js
> <li>cypress/e2e/Regression/ClientSide/Git/GitImport/GitImport_spec.js
>
<li>cypress/e2e/Regression/ClientSide/Git/GitSync/GitSyncGitBugs_spec.js
>
<li>cypress/e2e/Regression/ClientSide/Templates/ForkTemplateToGitConnectedApp.js
> <li>cypress/e2e/Regression/ClientSide/Widgets/Migration_Spec.js
> <li>cypress/e2e/Regression/ServerSide/ApiTests/API_MultiPart_Spec.ts
>
<li>cypress/e2e/Regression/ServerSide/ApiTests/API_TestExecuteWithDynamicBindingInUrl_spec.ts
> <li>cypress/e2e/Regression/ServerSide/OnLoadTests/JSOnLoad2_Spec.ts
>
<li>cypress/e2e/Regression/ServerSide/Params/PassingParams_Spec.ts</ol>
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/identified-flaky-tests-65890b3c81d7400d08fa9ee3?branch=master"
target="_blank">List of identified flaky tests</a>.
> <hr>Thu, 27 Mar 2025 15:43:27 UTC
<!-- end of auto-generated comment: Cypress test results  -->


## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [ ] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Improved recovery for repository operations by automatically reverting
to a stable state when errors occur, reducing conflict risks and
ensuring a consistent environment.
  
- **Refactor**
- Optimized the overall error handling and state management logic to
better maintain system stability during update and merge operations.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: nidhi-nair

app/server/appsmith-git/src/main/java/com/appsmith/git/service/ce/GitExecutorCEImpl.java

@@ -499,7 +499,7 @@ public Mono<MergeStatusDTO> pullApplication(
                                         }
                                     }
                                 })
-                                .onErrorResume(error -> Mono.error(error))
+                                .onErrorResume(error -> resetToLastCommit(git).flatMap(ignore -> Mono.error(error)))
                                 .timeout(Duration.ofMillis(Constraint.TIMEOUT_MILLIS))
                                 .name(GitSpan.FS_PULL)
                                 .tap(Micrometer.observation(observationRegistry)),
@@ -626,6 +626,15 @@ public Mono<GitStatusDTO> getStatus(Path repoPath, String branchName) {
                                         response.setRemoteBranch("untracked");
                                     }
 
+                                    // Remove modified changes from current branch so that checkout to other branches
+                                    // will be possible
+                                    if (!status.isClean()) {
+                                        return resetToLastCommit(git).map(ref -> {
+                                            processStopwatch.stopAndLogTimeInMillis();
+                                            jgitStatusSpan.end();
+                                            return response;
+                                        });
+                                    }
                                     processStopwatch.stopAndLogTimeInMillis();
                                     jgitStatusSpan.end();
                                     return Mono.just(response);
@@ -844,7 +853,13 @@ public Mono<String> mergeBranch(Path repoSuffix, String sourceBranch, String des
                                     }
                                 })
                                 .onErrorResume(error -> {
-                                    return Mono.error(error);
+                                    try {
+                                        return resetToLastCommit(repoSuffix, destinationBranch)
+                                                .thenReturn(error.getMessage());
+                                    } catch (GitAPIException | IOException e) {
+                                        log.error("Error while hard resetting to latest commit {0}", e);
+                                        return Mono.error(e);
+                                    }
                                 })
                                 .timeout(Duration.ofMillis(Constraint.TIMEOUT_MILLIS))
                                 .name(GitSpan.FS_MERGE)
@@ -1013,6 +1028,19 @@ public Mono<MergeStatusDTO> isMergeBranch(Path repoSuffix, String sourceBranch,
                                             mergeResult.getMergeStatus().name());
                                     return mergeStatus;
                                 })
+                                .flatMap(status -> {
+                                    try {
+                                        // Revert uncommitted changes if any
+                                        return resetToLastCommit(repoSuffix, destinationBranch)
+                                                .map(ignore -> {
+                                                    processStopwatch.stopAndLogTimeInMillis();
+                                                    return status;
+                                                });
+                                    } catch (GitAPIException | IOException e) {
+                                        log.error("Error for hard resetting to latest commit {0}", e);
+                                        return Mono.error(e);
+                                    }
+                                })
                                 .timeout(Duration.ofMillis(Constraint.TIMEOUT_MILLIS)),
                         Git::close)
                 .subscribeOn(scheduler);
@@ -1093,12 +1121,12 @@ private Mono<Ref> resetToLastCommit(Git git) {
                 .subscribeOn(scheduler);
     }
 
-    public Mono<Boolean> resetToLastCommit(Path repoSuffix, String branchName) {
+    public Mono<Boolean> resetToLastCommit(Path repoSuffix, String branchName) throws GitAPIException, IOException {
         return Mono.using(
                 () -> Git.open(createRepoPath(repoSuffix).toFile()),
                 git -> this.resetToLastCommit(git)
                         .flatMap(ref -> checkoutToBranch(repoSuffix, branchName))
-                        .thenReturn(true),
+                        .flatMap(checkedOut -> resetToLastCommit(git).thenReturn(true)),
                 Git::close);
     }
 
@@ -1128,7 +1156,7 @@ public Mono<Boolean> resetHard(Path repoSuffix, String branchName) {
     }
 
     public Mono<Boolean> rebaseBranch(Path repoSuffix, String branchName) {
-        return this.resetToLastCommit(repoSuffix, branchName).flatMap(isCheckedOut -> Mono.using(
+        return this.checkoutToBranch(repoSuffix, branchName).flatMap(isCheckedOut -> Mono.using(
                         () -> Git.open(createRepoPath(repoSuffix).toFile()),
                         git -> Mono.fromCallable(() -> {
                                     Span jgitRebaseSpan = observationHelper.createSpan(GitSpan.JGIT_REBASE);