This adds some optimisations and tests for the mdm commands UI feature.
This includes:
1. optimisations to making the request for the activity card data. We
add a stale time so the request is always occuring
2. consolidate PastCommandFeed and UpcomingCommandFeed to a single
CommandFeed component
3. adding aria label to buttons to improve a11y when buttons dont have
text (e.g. icon buttons)
4. tests for CommandFeed and FeedListItem components
5. change max-height of textarea in command details modal so it stays
within the viewport
