feat!: remove legacy library content block from component templates (#38930)

BREAKING CHANGE: Removes the 'library' template from the Studio add-component
strip so that new LegacyLibraryContentBlock instances can no longer be created via the UI.

- Removes 'library' from COMPONENT_TYPES
- Removes 'library' display name entry from component_display_names
- Removes the library block types loop (category == 'library')
- Removes 'library' from component_not_supported_by_library
- Removes the libraries_v1_enabled() filter from _filter_disabled_blocks

Existing library_content blocks continue to work normally, including the
randomized settings editor, "View all" container navigation, and migration
to v2 libraries. Only creation of new blocks via the add-component UI is
prevented.

Refs: https://github.com/openedx/openedx-platform/issues/38058
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>