Change design of compose form in web UI (#28119)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/mastodon/features/compose/containers/poll_button_container.js

@@ -4,7 +4,7 @@ import { addPoll, removePoll } from '../../../actions/compose';
 import PollButton from '../components/poll_button';
 
 const mapStateToProps = state => ({
-  unavailable: state.getIn(['compose', 'is_uploading']) || (state.getIn(['compose', 'media_attachments']).size > 0),
+  disabled: state.getIn(['compose', 'is_uploading']) || (state.getIn(['compose', 'media_attachments']).size > 0),
   active: state.getIn(['compose', 'poll']) !== null,
 });