fix: Add dark mode styling for nested menu items

[sfoslund]

Details

Update styling for menu items such that they adhere to dark mode. This effects the hierarchy settings and event settings menus that were identified in #1528.

Motivation

Addresses issue #1528

Context

[Image grid description: Screenshots of each menu before and after the styling change in dark and light modes]

	Before	After
Hierarchy settings in light mode
Hierarchy settings in dark mode
Event settings in light mode
Event settings in dark mode

Pull request checklist

• Run through of all test scenarios completed?
• Does this address an existing issue? If yes, [BUG] Hierarchy settings menu does not honor dark mode #1528
• Includes UI changes?
  • Run the production version of Accessibility Insights for Windows against a version with changes.
  • Attach any screenshots / GIF's that are applicable.

[DaveTryon]

I'm not getting the dark theming on the settings buttons in either live mode:

or in events mode:

Is it possible that a modified file didn't get pushed?

[DaveTryon]

We're close, but there's insufficient contrast between the menu hover color and the text hover color in the second tier of menus (see below)--maybe the second tier style should also update the text hover color?

[sfoslund]

@DaveTryon I've fixed the color contrast issue but I am not able to repro the issue you mentioned in your first comment- can you please provide repro steps if you're still seeing this?

[DaveTryon]

Thanks, @sfoslund! The problems I was having earlier seem to come from turning HC modes on and off while the app is running. I can still repro with some effort but it shouldn't be a blocker. I also found #1566 while testing these changes, but that's apparently an old bug unrelated to these changes.

One thought that might be very reasonably deferred--we now have something of a visual imbalance in how hover/selections are highlighted between the hierarchy control (highlight with contrast color) and the property control (highlight via bold text). Is it worth the effort to make them more consistent? We need to be mindful about not over-theming, since we also have context menus in non-themed dialogs.