fix(ui, localization): remove redundant platform configuration

[pcj]

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• Code changes are tested (add some information if not applicable)

Description of the pull request

Package stream_chat_flutter:windows references stream_chat_flutter:windows as the default plugin, but it does not provide an inline implementation.
Ask the maintainers of stream_chat_flutter to either avoid referencing a default implementation via `platforms: windows: default_package: stream_chat_flutter` or add an inline implementation to stream_chat_flutter via `platforms: windows:` `pluginClass` or `dartPluginClass`.
Package stream_chat_flutter:android references stream_chat_flutter:android as the default plugin, but it does not provide an inline implementation.
Ask the maintainers of stream_chat_flutter to either avoid referencing a default implementation via `platforms: android: default_package: stream_chat_flutter` or add an inline implementation to stream_chat_flutter via `platforms: android:` `pluginClass` or `dartPluginClass`.
Package stream_chat_flutter:ios references stream_chat_flutter:ios as the default plugin, but it does not provide an inline implementation.
Ask the maintainers of stream_chat_flutter to either avoid referencing a default implementation via `platforms: ios: default_package: stream_chat_flutter` or add an inline implementation to stream_chat_flutter via `platforms: ios:` `pluginClass` or `dartPluginClass`.
Package stream_chat_flutter:linux references stream_chat_flutter:linux as the default plugin, but it does not provide an inline implementation.
Ask the maintainers of stream_chat_flutter to either avoid referencing a default implementation via `platforms: linux: default_package: stream_chat_flutter` or add an inline implementation to stream_chat_flutter via `platforms: linux:` `pluginClass` or `dartPluginClass`.
Package stream_chat_flutter:macos references stream_chat_flutter:macos as the default plugin, but it does not provide an inline implementation.
Ask the maintainers of stream_chat_flutter to either avoid referencing a default implementation via `platforms: macos: default_package: stream_chat_flutter` or add an inline implementation to stream_chat_flutter via `platforms: macos:` `pluginClass` or `dartPluginClass`.
Package stream_chat_flutter:windows references stream_chat_flutter:windows as the default plugin, but it does not provide an inline implementation.

Similar to:

• I was told to ask you to either avoid a reference or create a plugin (I am serious :) MaikuB/flutter_local_notifications#2368
• https://github.com/Abdelazeem777/cached_network_svg_image/pull/12/files

[pcj]

Can confirm this fixes the warnings on my private repo. I looked through other pubspec.yaml files in the repo and also included stream_chat_localizations.