Dropdown Drawer - change the account selection UI to dropdown list

[wmontwe]

The account selection should open a dropdown list of accounts instead of the siderail.

[karthikb1612]

Hi, I saw this task and I’d love to take it up.
Could you please confirm if I can start working on it or if someone is already assigned?
Thanks!

[kewisch]

Wolf is currently working on this for this week so it might not be the best issue to tackle. If you'd like to help us with the drawer then I think the best approach would be stress-testing the current functionality in the dropdown drawer (enabled on debug/daily/beta). We've been getting a few crash reports that have been difficult/impossible to reproduce. Another area that could be interesting is expanding on the new Jetpack Glance based widget that was started in #8719 . It needs a little more testing, fixing some of the edge cases where content is not loading, and making sure all of the (relevant) features from the old widget are ported. Please drop by in #tb-android-dev:mozilla.org on Matrix if you want to chat about this further.