[Refactor] Slash-n-Burn Annotatable BuiltIn XBlock

[irfanuddinahmad]

See parent epic: openedx/openedx-platform#37819

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Rollout Position

Step 3 of 8 — Small-medium footprint (~924 LOC core + vendored annotator.js files). Before removing, verify that xmodule/annotator_mixin.py is not used by any other remaining block.

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Block Details

Toggle	USE_EXTRACTED_ANNOTATABLE_BLOCK in openedx/envs/common.py
Shim class	_BuiltInAnnotatableBlock in xmodule/annotatable_block.py
Entrypoint	annotatable = "xmodule.annotatable_block:AnnotatableBlock" in pyproject.toml

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Checklist

Pre-condition

• Review PRs merged into the built-in Annotatable XBlock code in edx-platform after the extraction work was done — port any bug fixes or improvements to xblocks-contrib if not already there.
• Confirm xmodule/annotator_mixin.py is not referenced by any other remaining block.

Steps (single PR)

• Remove the toggle — delete USE_EXTRACTED_ANNOTATABLE_BLOCK from openedx/envs/common.py and all usages.
• Remove the shim — delete _BuiltInAnnotatableBlock class and the from xblocks_contrib.annotatable import AnnotatableBlock as _ExtractedAnnotatableBlock import from xmodule/annotatable_block.py.
• Remove the entrypoint — delete annotatable = "xmodule.annotatable_block:AnnotatableBlock" from pyproject.toml.
• Remove remaining assets:
  • xmodule/annotatable_block.py (Python class)
  • xmodule/annotator_mixin.py (mixin — only if no other block depends on it)
  • xmodule/js/src/annotatable/display.js (JavaScript)
  • common/static/js/vendor/annotator.*.js files (7 vendored Annotator.js files)
  • common/static/css/vendor/edxnotes/annotator.min.css
  • lms/templates/annotatable.html (template)
  • xmodule/static/css-builtin-blocks/AnnotatableBlockDisplay.css
  • xmodule/static/css-builtin-blocks/AnnotatableBlockEditor.css
  • Webpack entries AnnotatableBlockDisplay / AnnotatableBlockEditor in webpack.builtinblocks.config.js
• Run smoke tests on the extracted Annotatable block to verify nothing is broken.

[irfanuddinahmad]

Implementation PR: openedx/openedx-platform#38746