Using grid layout moves us away from fixed widths
and position for items where possible, which will
make it easier to make messagebox changes without
breaking formatting.
Visual changes expected in this commit:
- When the action buttons overlap the message content,
it will no longer visually overlap but completely cut off
the content — which is good, but means the messages can’t
be as wide on narrow width views. There’s a slight improvement
to this in an upcoming commit.
Also removes the `last_message` CSS, which was busted due to the
`last_message` calculation not correctly being updated for new
messages arriving, and didn't improve styling.
Aman Agrawal