[Browser] Improve incognito mode color scheme for dropdowns

[sunleos]

More details of the scope:

@Rsttskyy to

@Khushboo-dev-cpp, @sunleos,

Added menus, for dropdown, bookmark, and basic rules for any other dropdowns in incognito light/dark
https://www.figma.com/design/pJgiysu3rw8XvL4wS2Us7W/DS?node-id=3767-49095&t=qu04VYLaey35FL9b-1

we're applying same rules with 3 color + adding updated unified for error which can use on light and dark incognito.

FYI I think with submit buttons (like adding/edit bookmark for example) we need to change logic globally across all application because opacity of blue/red not working when we're changing background, and need to make universal solution when we'll start working with container tabs. I would not touch submit buttons for now.