feat(ui, core, localization): add draft message preview and controller

[xsahil03x]

Resolves: FLU-98, FLU-99

Description of the pull request

This pull request adds UI, Core support for the draft messages feature.

Screen.Recording.2025-04-28.at.14.34.30.mov

[github-actions]

⚠️ Database Entity Files Modified

The following database entity files have been modified in this PR:

packages/stream_chat_persistence/lib/src/entity/draft_messages.dart

📝 Remember to:

1. Update database version in db/drift_chat_database.dart.
2. Update entity schema tests if necessary.

Note: This comment is automatically generated by the CI workflow.

[codecov]

Codecov Report

Attention: Patch coverage is 70.61503% with 129 lines in your changes missing coverage. Please review.

Project coverage is 63.05%. Comparing base (7d8c556) to head (0d4b03c).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...view/draft_scroll_view/stream_draft_list_view.dart	1.66%	59 Missing ⚠️
...er/lib/src/message_input/stream_message_input.dart	46.00%	27 Missing ⚠️
.../channel_scroll_view/stream_channel_list_tile.dart	0.00%	12 Missing ⚠️
...core/lib/src/stream_thread_list_event_handler.dart	0.00%	12 Missing ⚠️
...t_flutter/lib/src/theme/draft_list_tile_theme.dart	84.00%	8 Missing ⚠️
...ter_core/lib/src/stream_draft_list_controller.dart	95.78%	4 Missing ⚠️
packages/stream_chat/lib/src/client/channel.dart	90.00%	2 Missing ⚠️
...ew/thread_scroll_view/stream_thread_list_tile.dart	93.75%	2 Missing ⚠️
...er_core/lib/src/stream_thread_list_controller.dart	0.00%	2 Missing ⚠️
..._core/lib/src/stream_message_input_controller.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2230      +/-   ##
==========================================
+ Coverage   62.98%   63.05%   +0.06%     
==========================================
  Files         394      400       +6     
  Lines       24776    25124     +348     
==========================================
+ Hits        15606    15842     +236     
- Misses       9170     9282     +112     

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