UI: Unify appearance of menus

[Warchamp7]

Description

Cleans up the appearance of the top menu bar menus, right-click context menus, and dropdown menus. Also brings them all generally in line with each other visually.

Note

Due to the changes to dropdown menus here, we may want to hold off on merging this until I can get around to adding padding adjustment to the Appearance settings. Maybe.

Motivation and Context

Hate weird paddings and small visual differences.

Before	After

Before	After

Before	After

How Has This Been Tested?

👁

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.