Cherry-pick BROS-780 fix to lse-release/2.33.0

## Request

Please cherry-pick commit `cd31ff536d61348286850a66def2f100c508ef7a` (PR #9373 - fix: BROS-780: Fix custom tab detection after merge conflict) into the `lse-release/2.33.0` branch.

## Details

- **Source Commit**: `cd31ff536d61348286850a66def2f100c508ef7a`
- **Source Branch**: develop
- **Target Branch**: lse-release/2.33.0
- **New Branch Name**: `lse-release-2.33.0-fb-bros-814-sidebar`

## Patch File

A patch file has been prepared and is available in the label-studio-enterprise repository at:
https://github.com/HumanSignal/label-studio-enterprise/blob/lse-release-2.33.0-fb-bros-814-sidebar/bros-814-sidebar.patch

## Steps to Apply

```bash
git checkout -b lse-release-2.33.0-fb-bros-814-sidebar origin/lse-release/2.33.0
git cherry-pick cd31ff536d61348286850a66def2f100c508ef7a
git push -u origin lse-release-2.33.0-fb-bros-814-sidebar
```

## Related

This is needed for the LSE release branch preparation. Once this branch is pushed, the LSE repository's `web/package.json` will be updated to reference the new commit SHA.

Related LSE branch: https://github.com/HumanSignal/label-studio-enterprise/tree/lse-release-2.33.0-fb-bros-814-sidebar