refactor: OPTIC-927: Remove Stale Feature Flag - ff_front_dev_2432_auto_save_polygon_draft_210622_short

[luarmr]

PR fulfills these requirements

• 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
• Tests for the changes have been added/updated (for bug fixes/features)
• Docs have been added/updated (for bug fixes/features)
• Best efforts were made to ensure docs/code are concise and coherent (checked for spelling/grammatical errors, commented out code, debug logs etc.)
• 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)
• 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]

Codecov Report

Attention: Patch coverage is 45.94595% with 40 lines in your changes missing coverage. Please review.

Project coverage is 76.67%. Comparing base (fae09df) to head (a9ef4d6).
Report is 41 commits behind head on develop.

Files with missing lines	Patch %	Lines
..._studio/core/management/commands/locked_migrate.py	0.00%	30 Missing ⚠️
label_studio/core/label_config.py	73.91%	6 Missing ⚠️
label_studio/core/utils/common.py	66.66%	2 Missing ⚠️
label_studio/tasks/models.py	66.66%	1 Missing ⚠️
label_studio/users/models.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6581      +/-   ##
===========================================
- Coverage    76.72%   76.67%   -0.05%     
===========================================
  Files          169      169              
  Lines        13818    13846      +28     
===========================================
+ Hits         10602    10617      +15     
- Misses        3216     3229      +13     

Flag	Coverage Δ
pytests	76.67% <45.94%> (-0.05%)	⬇️

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[luarmr]

Thanks @yyassi-heartex for pin point
#6584

[luarmr]

/git merge

Workflow run
Successfully merged: create mode 100644 web/libs/editor/src/components/SidePanels/DetailsPanel/TimelineRegionEditor.tsx