Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `app/javascript/mastodon/features/compose/components/poll_form.js`:
  glitch-soc change because of having changed the default number of
  available poll options.
  Applied upstream's changes while keeping glitch-soc's default number of
  poll options.
- `public/oops.png`:
  We had a minor graphics change, probably not worth diverging from upstream.
  Took upstream version.

app/javascript/mastodon/features/compose/components/poll_form.js

@@ -157,7 +157,7 @@ class PollForm extends ImmutablePureComponent {
         </ul>
 
         <div className='poll__footer'>
-          <button disabled={options.size >= 5} className='button button-secondary' onClick={this.handleAddOption}><Icon id='plus' /> <FormattedMessage {...messages.add_option} /></button>
+          <button type='button' disabled={options.size >= 5} className='button button-secondary' onClick={this.handleAddOption}><Icon id='plus' /> <FormattedMessage {...messages.add_option} /></button>
 
           {/* eslint-disable-next-line jsx-a11y/no-onchange */}
           <select value={expiresIn} onChange={this.handleSelectDuration}>