Add Widget support

[toger5]

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Tests

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Checklist

• This PR was made with the help of AI:
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  • No.
• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
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• Pull request title will be used in the release note, it clearly defines what will change for the user
• Pull request includes screenshots or videos if containing UI changes
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[github-actions]

Thank you for your contribution! Here are a few things to check in the PR to ensure it's reviewed as quickly as possible:

• If your pull request adds a feature or modifies the UI, this should have an equivalent pull request in the Element X iOS repo unless it only affects an Android-only behaviour or is behind a disabled feature flag, since we need parity in both clients to consider a feature done. It will also need to be approved by our product and design teams before being merged, so it's usually a good idea to discuss the changes in a Github issue first and then start working on them once the approach has been validated.
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[bmarty]

Hello @toger5, thanks for the PR. What is the plan about it? I see that they are some changes in the Rust SDK, so maybe a plan could be to:

• release the SDK with the requested change
• hide access to the new Extensions screen behind a feature flag
• review and merge this PR

Asking because this feature can be useful to handle the calls using Jitsi.

WDYT?