Allow switching accounts from the post composer

[gesteves]

Is your feature request related to a problem? Please describe.

Sometimes I start writing a post and then realize I'm logged into the wrong account. This can be particularly annoying if it's a reply, since then I have to exit the composer, switch accounts, find the post I wanted to reply to, and then re-type my post. It'd be nice to be able to quickly switch accounts from the post composer without losing what I've typed so far.

Describe the solution you'd like

Perhaps tapping my avatar in the composer could open the account switcher so I could quickly select which account to post from.

Describe alternatives you've considered

1. Copy the post I wrote to the clipboard
2. Switch accounts
3. If I was replying to someone, go find the post I wanted to reply to
4. Paste the text I had written (or write it from scratch)
5. Publish the post

Additional context

N/A