Polish and tweak new annotations UX

A new annotations UX was introduced with !105 (merged) and overall it is a major improvement. Nonetheless, I have a few suggestions to take it to the next level:

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When you use a quick annotation from the toolbar pop-up menu, it immediately shows the full annotations toolbar. This feels a little odd, because it's invoking an action that you didn't expect in addition to doing what you want. Suggestion: don't do this, and instead add a new "Show all tools" menu item to the "Quick Annotations" dropdown menu which will show the full toolbar when invoked.

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The toolbar item's text "Quick annotations" might be a bit long, and it also doesn't begin with a verb as actions are supposed to do. Perhaps we could consider changing it to "Annotate..." (with ellipses, because more user input will be required before the action completes).

cc @teams/vdg