feat(nimbus): add analaysis window indicator inside metric name cards

[moibra05]

Because

• It's often times unclear which analysis window is currently being displayed for a metric's results

This commit

• Adds a text indicator that tells us which analysis window is being reflected in the main page results

Fixes #14850

[moibra05]

[mikewilli]

Are these always accurate based on the data available? Like what happens on Day 3? Do we show "Day 4" for RETENTION_3_DAYS, or do we just show nothing? And I'm fairly sure Week 2 for Retention could be wrong in some cases because we haven't done #12647 yet, so it could be Week 1 (the old Results page always said Week 2 Retention so maybe we don't need to block on this).

I just want to make sure we aren't going to be potentially showing the wrong thing for early or wonky (missing days/weeks) results.

[moibra05]

fair points. the changes im making in #15050 will make it so 3day retention will remain unavailable until day 4 data is available so it will show nothing on Day <4 or if the metric has no data (this goes for all metrics). in that case i think the most logical thing to do would be to complete #15050 and #12647 before this

[mikewilli]

There was some recent confusion on what the Overview section of the metric details modal is showing -- can/should we tack something on to this PR to update that too? Or file a new ticket?

[moibra05]

i think we can just include that change in this pr and broaden the scope/title to covering general improvements to analysis window representation