External Storage Sync (GCS) Not Deleting or Updating Tasks

**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Steps to reproduce the behavior:
1. Connect your GCS Bucket/Storage
2. Add a JSON task (single JSON apprarently only supports 1 task for GCS)
3. Go to Data Manager, the task gets displayed.
4. Delete the JSON from the GCS bucket.
5. Make changes to the task.
6. Upload to GCS bucket again.
7. Sync the bucket (Syncs successfully).
8. Go to data manager and see the tasks.
9. [Problem] --> Previous tasks do not go away, syncing again just adds the tasks.
10. Repeat from 4, tasks just keep getting added.

**Expected behavior**
The sync should reflect the state of the bucket/storage that was updated. Here, this translates to the previous tasks getting deleted and and only the current ones in the bucket to be present.

**Screenshots**

The tasks that remain to persist have different sources as well (as seen from these `` brackets). Of all these 3 tasks shown, my GCS bucket has JSON for only one of them. Where / Why are the rest coming from.

**Environment (please complete the following information):**
- OS: NA (Running enterprise edition from `app.heartex.com`)
``` JSON
{
"release": "2.11.2.dev1",
"label-studio-os-package": {
"version": "1.12.1.dev0",
"short_version": "1.12",
"latest_version_from_pypi": null,
"latest_version_upload_time": null,
"current_version_is_outdated": false
},

"label-studio-os-backend": {
"message": "fix: LEAP-921: Fix the way of updating users in store (#5776)",
"commit": "b9fe20227662296cbc9ff7d2306718ad5e1f137b",
"branch": "develop",
"date": "2024-05-06 13:14:11",
"version": "b9fe202"
},

"label-studio-frontend": {
"message": "fix: LEAP-921: Fix the way of updating users in store (#5776)",
"commit": "b9fe20227662296cbc9ff7d2306718ad5e1f137b",
"date": "2024-05-06T13:14:11.000Z",
"branch": "develop"
},

"dm2": {
"message": "fix: LEAP-921: Fix the way of updating users in store (#5776)",
"commit": "b9fe20227662296cbc9ff7d2306718ad5e1f137b",
"date": "2024-05-06T13:14:11.000Z",
"branch": "develop"
},

"label-studio-converter": {
"version": "0.0.58"
},

"label-studio-enterprise-backend": {
"message": "fix: LEAP-921: Fix the way of updating users in store (#5646)",
"commit": "7f70a3f0d985aae9ac9b5ad2ba17a47c1f12f164",
"date": "2024-05-06 16:34:01",
"branch": "refs/heads/gh-readonly-queue/develop/pr-5646-912d73eed3fb5f8eaa8d6d92a9b49d8f632ca1b8",
"version": "20240506.163824-gh-readonly-queue-develop-7f70a3f0d"
},

"label-studio-enterprise-package": {
"version": "20240506.163824-gh-readonly-queue-develop-7f70a3f0d"
},

"label-studio-react-app": {
"message": "fix: LEAP-921: Fix the way of updating users in store (#5646)",
"commit": "7f70a3f0d985aae9ac9b5ad2ba17a47c1f12f164",
"date": "2024-05-06T16:34:01.000Z",
"branch": "develop"
}
}

```

**Additional context**
- My GCS storage was added with the "regex" of `.*json`.