Support multi-select polls

[bxdxnn]

Content

Support max_selections for polls

Motivation and context

element-hq/element-meta#2694
Fixes #6278

Screenshots / GIFs

Tests

• Test if you can create polls with max_selections
• Test if you can select only up to the count of max_selections

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• This PR was made with the help of AI:
  • Yes. In this case, please request a review by Copilot.
  • 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
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• 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
• You've made a self review of your PR

[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.
• Your branch should be based on origin/develop, at least when it was created.
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• The test pass locally running ./gradlew test.
• The code quality check suite pass locally running ./gradlew runQualityChecks.
• If you modified anything related to the UI, including previews, you'll have to run the Record screenshots GH action in your forked repo: that will generate compatible new screenshots. However, given Github Actions limitations, it will prevent the CI from running temporarily, until you upload a new commit after that one. To do so, just pull the latest changes and push an empty commit.

[frebib]

This is pretty huge. Thanks for implementing this.
Edit: just tried it and it works amazingly

[ganfra]

@mxandreas Would that be ok to have this? I guess we need the same for iOS to stay consistent

[mxandreas]

This is pretty huge. Thanks for implementing this. Edit: just tried it and it works amazingly

Yes, it would be great to have it, but it is something that needs to be supported cross-platform, including web. Otherwise it can cause more frustration or confusion to users as it is always between multiple users. I can check if web is tackling soon or not.

[bxdxnn]

@mxandreas I could try implementing it on iOS as well if the flow of this implementation is what's expected.

[mxandreas]

@ganfra Could this be deployed so I can test it?

[bxdxnn]

@mxandreas you can download a debug APK to test from here.

[mxandreas]

The overall experience looks quite straightforward. @americanrefugee check out the video below just in case if you spot anything from the UI side. I think the main obstacle is that this needs to be supported on cross-platform before it can be released, otherwise it is very confusing. Hopefully it is not too difficult to get it working also on iOS and Web.

[americanrefugee]

Please change the bg color of the selected state to color/bg/accent/rest

cc @amshakal (who worked on polls in the past)

[bxdxnn]

I have successfully tested the Web and Android versions, waiting for code review now.