Extend Rust to Dart error propagation

[alexlapa]

Synopsis

Задача завершающая цикл задач (#204, #205, #198) по прокидыванию ошибок из внешнего API Jason'а в Dart.

Solution

Добавлены:

1. MediaStateTransitionException который может вылетать из RoomHandle enable / disable / mute / unmute local / remote audio / video методов.
2. InternalException для случаев когда ломается то, что ломаться не должно. По идее, мы ее никогда не увидим.
3. MediaSettingsUpdateException который вылетает из RoomHandle.set_local_media_settings()

Checklist

• Created PR:
  • [x] In draft mode
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  • [x] Has k:: labels applied
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• [x] Documentation is updated (if required)
• [x] Tests are updated (if required)
• [x] Changes conform code style
• [x] CHANGELOG entry is added (if required)
• [x] FCM (final commit message) is posted
  • [x] and approved
• [x] Review is completed and changes are approved
• Before merge:
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  • [x] Draft: prefix is removed
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[alexlapa]

FCM:

Extend Rust to Dart error propagation (#213)

- throw MediaStateTransitionException from RoomHandle enable / disable / mute / unmute local / remote audio / video methods
- throw MediaSettingsUpdateException from RoomHandle.set_local_media_settings()
- throw InternalException in cases of programmatic errors or unexpected platform failures