refactor: OPTIC-1415: Remove Stale Feature Flag - ff_back_dev_3865_filters_anno_171222_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.
Pushing this code against after develop being back again

WHEN REVIEW
CHECK THE STALE VALUE FIRST

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✅ Deploy Preview for heartex-docs canceled.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.77%. Comparing base (83ee25a) to head (09063a5).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #6758   +/-   ##
========================================
  Coverage    76.77%   76.77%           
========================================
  Files          170      170           
  Lines        13944    13944           
========================================
  Hits         10706    10706           
  Misses        3238     3238           

Flag	Coverage Δ
pytests	76.77% <ø> (ø)

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