[9.1][Automation] Update versions (#9334)

* [9.1][Automation] Update versions

These files are used for picking the starting (pre-upgrade) or ending (post-upgrade) agent versions in upgrade integration tests.

The content is based on responses from https://www.elastic.co/api/product_versions and https://snapshots.elastic.co

The current update is generated based on the following requirements:

Package version: ```json
{
  "version": "9.1.2-SNAPSHOT",
  "build_id": "9.1.2-a690164d",
  "manifest_url": "https://snapshots.elastic.co/9.1.2-a690164d/manifest-9.1.2-SNAPSHOT.json",
  "summary_url": "https://snapshots.elastic.co/9.1.2-a690164d/summary-9.1.2-SNAPSHOT.html",
  "core_version": "9.1.2",
  "stack_build_id": "9.1.2-a690164d-SNAPSHOT"
}
```

```json
{
  "UpgradeToVersion": "9.1.2",
  "CurrentMajors": 1,
  "PreviousMajors": 1,
  "PreviousMinors": 2,
  "SnapshotBranches": [
    "9.1",
    "9.0",
    "8.19",
    "7.17"
  ]
}
```

* temporary revert of test-versions

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Panos Koutsovasilis <[email protected]>

Author: github-actions[bot]

.package-version

@@ -1,8 +1,8 @@
 {
-  "version": "9.1.1-SNAPSHOT",
-  "build_id": "9.1.1-e8fd9f6e",
-  "manifest_url": "https://snapshots.elastic.co/9.1.1-e8fd9f6e/manifest-9.1.1-SNAPSHOT.json",
-  "summary_url": "https://snapshots.elastic.co/9.1.1-e8fd9f6e/summary-9.1.1-SNAPSHOT.html",
-  "core_version": "9.1.1",
-  "stack_build_id": "9.1.1-e8fd9f6e-SNAPSHOT"
+  "version": "9.1.2-SNAPSHOT",
+  "build_id": "9.1.2-a690164d",
+  "manifest_url": "https://snapshots.elastic.co/9.1.2-a690164d/manifest-9.1.2-SNAPSHOT.json",
+  "summary_url": "https://snapshots.elastic.co/9.1.2-a690164d/summary-9.1.2-SNAPSHOT.html",
+  "core_version": "9.1.2",
+  "stack_build_id": "9.1.2-a690164d-SNAPSHOT"
 }