Update visuals of bubble bar education views

- update colours to match spec
- update sizes to match spec
- update elevation

Flag: com.android.wm.shell.enable_bubble_bar
Test: manual - flash wipe, get a bubble, tap on it and observe user
               education, expand the bubble, observe the manage menu
               user education, repeat with dark theme
Bug: 372516663
Fixes: 374856431
Change-Id: I726a71cb0a0528358ccc235fe8eb0778280a79e1