* Add new attachments selection dialog
* Add rounded corners to bottom sheet dialog.
Note these are currently only visible in the collapsed state.
- [Google issue](https://issuetracker.google.com/issues/144859239)
- [Rejected PR](https://github.com/material-components/material-components-android/pull/437)
- [Github issue](https://github.com/material-components/material-components-android/issues/1278)
* Add changelog entry
* Remove redundant call to superclass click listener
* Refactor to use view visibility helper
* Change redundant sealed class to interface
* Remove unused string
* Revert "Add rounded corners to bottom sheet dialog."
This reverts commit 17c43c9188.
* Remove redundant view group
* Remove redundant `this`
* Update rich text editor to latest
* Update rich text editor version
* Allow toggling rich text in the new editor
* Persist the text formatting setting
* Add changelog entry
