Part of a stack of diffs to fix the timestamp bug, related Linear issue here.
This diff moves the timestamp tooltip below the message tooltip (with the reply and create thread buttons). Handling other front-end changes like color will be handled in subsequent diffs in this stack, this diff is just focused on aligning the tooltip correctly.
Depends on D4481.
For other tooltip actions we don't need to manually set this style. Can we use the mechanism we already have, or are there any reasons for not doing so?