Improve annotation UX in insights

[corywatilo]

Tooltip interaction

Problem
When hovering an annotation, there's a button that says "Add Note". Because it displays on hover, you'd assume you can move your mouse to it (like a dropdown navigation menu). Instead, it disappears because you actually have to click it first, which isn't obvious from how it's presented.

Proposed solution
Allow the tooltip to stay open without having to first click it

Annotation wording

Problem
It's unclear if a "Note" is the same things as an "Annotation". When adding a "note", it looks like you're adding a comment on a thread.

Solution
Rename "Note" to "Annotation" to make it clear you're actually adding an additional annotation.

New annotation modal is too narrow

Already filed under #8568, but seems like these could all be knocked out together