fix wave coldboot and wave surface recreation bg color reset

[Kethen]

Do not set background color during cxl_bg_start since android would re-invoke onSurfaceCreated every time the view transitions from invisible to visible

Wave background cold boot seems to have been lost during the last refactoring, adding that back as well

Thanks for working on this launcher, it looks amazing :ok_hand:

[EmiyaSyahriel]

Thank you! I didn't know this problem could happen because this part of code is written at 1AM and the problem never shows up during my own testing and I also missed it during refactoring, my bad 😅, Merging it now~