extensions: use buttons for non-link actions

Created by: tjkandala

Part of #36751 (closed). Closes #34054 (closed) and #36752 (closed).

Looked like a codemod for class="btn" wrapped <ActionItem>s in <SearchResultsInfoBar> with <Button>. We used to pass that style down to <ButtonLink>, which renders <a>s for everything :(.

I refactored <ActionItem> to render <Button> when the extension action isn't navigation.

I also did some migration from data-tooltip to our new wildcard <Tooltip>. I found that wrapping action items with <Tooltip> affects styles due to insertion of the target <span>. This broke the adjacent sibling combinator (+) in hover overlay for buttons like "Find references" and "Find implementations". What is FPTs suggestion for such styles? I just added the ml-1 class to hover overlay buttons that aren't the first in <HoverOverlay>, but I wonder if there's a pure CSS solution.

Test plan

Manually tested all components that use <ActionItem> in both the webapp and browser extension, automated tests pass.

Manual testing results

Component	Before	After
<SearchResultsInfoBar>
<HoverOverlay>
<CommandList>
<ActionItemsBar>
Action items on BExt

Changes

• Slight increase in command list font weight, but that aligns with our other buttons so it should be ok.
• Browser extension action items look better somehow? Might be the icon centering.

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.