* Add plain text representation of messages.
This is used in the room list as the last message in a room, in the message summary when a message is selected, in the 'replying to' block, in the 'replied to' block in a message in the timeline, and in notifications.
<!-- Please read [CONTRIBUTING.md](https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md) before submitting your pull request -->
## Type of change
- [x] Feature
- [ ] Bugfix
- [ ] Technical
- [ ] Other :
## Content
Polls can now be replied to.
## Motivation and context
User story: https://github.com/vector-im/element-meta/issues/1976
## Screenshots / GIFs
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## Tests
<!-- Explain how you tested your development -->
- Step 1
- Step 2
- Step ...
## Tested devices
- [ ] Physical
- [ ] Emulator
- OS version(s):
## Checklist
<!-- Depending on the Pull Request content, it can be acceptable if some of the following checkboxes stay unchecked. -->
- [ ] Changes have been tested on an Android device or Android emulator with API 23
- [ ] UI change has been tested on both light and dark themes
- [ ] Accessibility has been taken into account. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
- [ ] Pull request is based on the develop branch
- [ ] Pull request includes a new file under ./changelog.d. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#changelog
- [ ] Pull request includes screenshots or videos if containing UI changes
- [ ] Pull request includes a [sign off](https://matrix-org.github.io/synapse/latest/development/contributing_guide.html#sign-off)
- [ ] You've made a self review of your PR
