Delete the old implementation of the QS footer actions

This CL deletes the old code of the QS footer actions. The new Compose
implementation has been enabled since September in ag/24789232.

Bug: 293569320
Test: N/A. Pure code deletion.
Flag: EXEMPT deletes unused code turned off by legacy flag.
Change-Id: If96a18f57543549ca19aa10557d03f6d23e782f0