UIUX: Add loading indicator beyond the moving Pacman

The Pacman screen itself does not give any indication on how much longer to wait (approximately).

Inspiration from Trezor Suite loading screen (when updating):

No source file, test, or entry point is named. Start by locating the Pacman loading screen in the desktop UI and read how its current animation is driven; done means the screen gives users an approximate indication of remaining wait time, consistent with the attached inspiration.

Written by the indexing model from the issue text.