Fix crash when error happens during reading databricks_job (#5110)

## Changes
<!-- Summary of your changes that are easy to understand -->

The crash occurred when reading a job and backend returned an error, so
the `job` became `nil`, but we still tried to access fields inside the
struct, instead of returning the error immediately.

## Tests
<!--
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->

- [x] `make test` run locally
- [ ] relevant change in `docs/` folder
- [ ] covered with integration tests in `internal/acceptance`
- [ ] using Go SDK
- [ ] using TF Plugin Framework
- [x] has entry in `NEXT_CHANGELOG.md` file

Author: alexott

NEXT_CHANGELOG.md

@@ -8,6 +8,8 @@
 
 ### Bug Fixes
 
+* Fix crash when error happens during reading `databricks_job` ([#5110](https://github.com/databricks/terraform-provider-databricks/pull/5110))
+
 ### Documentation
 
 * Document `git_email` in `databricks_git_credential` resource ([#5099](https://github.com/databricks/terraform-provider-databricks/pull/5099))

jobs/jobs_api_go_sdk.go

@@ -313,6 +313,9 @@ func Read(jobID int64, w *databricks.WorkspaceClient, ctx context.Context) (job
 		JobId: jobID,
 	})
 	err = wrapMissingJobError(err, fmt.Sprintf("%d", jobID))
+	if err != nil {
+		return
+	}
 	if job.Settings != nil {
 		js := JobSettingsResource{JobSettings: *job.Settings}
 		js.adjustTasks()

jobs/resource_job_test.go

@@ -2372,6 +2372,37 @@ func TestResourceJobRead_NotFound(t *testing.T) {
 	}.ApplyNoError(t)
 }
 
+func TestResourceJobReadMultiTask_NotFound(t *testing.T) {
+	qa.ResourceFixture{
+		MockWorkspaceClientFunc: func(w *mocks.MockWorkspaceClient) {
+			e := w.GetMockJobsAPI().EXPECT()
+			e.Get(mock.Anything, jobs.GetJobRequest{
+				JobId: 789,
+			}).Return(nil, apierr.ErrNotFound)
+		},
+		Resource: ResourceJob(),
+		HCL: `
+		name = "Featurizer"
+		task {
+			task_key = "a"
+			spark_jar_task {
+				main_class_name = "com.labs.BarMain"
+			}
+		}
+		task {
+			task_key = "b"
+			notebook_task {
+				notebook_path = "/Stuff"
+			}
+		}`,
+
+		Read:    true,
+		New:     true,
+		Removed: true,
+		ID:      "789",
+	}.ApplyNoError(t)
+}
+
 func TestResourceJobRead_Error(t *testing.T) {
 	d, err := qa.ResourceFixture{
 		Fixtures: []qa.HTTPFixture{