refactor: OPTIC-921: Remove Stale Feature Flag - fflag_feat_front_dev_4081_magic_wand_tool

[luarmr]

PR fulfills these requirements

• [x] Commit message(s) and PR title follows the format [fix|feat|ci|chore|doc]: TICKET-ID: Short description of change made ex. fix: DEV-XXXX: Removed inconsistent code usage causing intermittent errors
• [x] Tests for the changes have been added/updated (for bug fixes/features)
• [x] Docs have been added/updated (for bug fixes/features)
• [x] Best efforts were made to ensure docs/code are concise and coherent (checked for spelling/grammatical errors, commented out code, debug logs etc.)
• [x] Self-reviewed and ran all changes on a local instance (for bug fixes/features)

Change has impacts in these area(s)

(check all that apply)

• [ ] Product design
• [ ] Backend (Database)
• [ ] Backend (API)
• [x] Frontend

Describe the reason for change

Removing a FF that was stale for a few months.

WHEN REVIEW CHECK THE STALE VALUE FIRST

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 76.77%. Comparing base (7479e3e) to head (686210f). Report is 4 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #6701 +/- ## ======================================== Coverage 76.77% 76.77% ======================================== Files 170 170 Lines 13883 13883 ======================================== Hits 10659 10659 Misses 3224 3224 ``` | [Flag](https://app.codecov.io/gh/HumanSignal/label-studio/pull/6701/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=HumanSignal) | Coverage Δ | | |---|---|---| | [pytests](https://app.codecov.io/gh/HumanSignal/label-studio/pull/6701/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=HumanSignal) | `76.77% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=HumanSignal#carryforward-flags-in-the-pull-request-comment) to find out more.

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