Revert "Adjust menubaritem style to be more in line with the more subdued look...

Revert "Adjust menubaritem style to be more in line with the more subdued look of other UI elements"

This reverts commit c8a5b48a.

This commit was mostly added because its author (me) wanted another person to "shut up"
in regards to their strong opinion about the appearance of a UI element they seldom use,
and not because they thought it was an improvement to the UI element or that it made the
UI element more consistent with others.

That was a mistake.

The commit introduces huge contrast issues w/ menubar items, where it's hard to tell that
they're being hovered or are currently opened, especially in sunlight.

This goes back to the prior status quo, where the menubar's state is easily read in all
environments.