Hide freeform button from app menu in recents

When desktop windowing prototype is enabled, we should only be able to
switch apps to freeform mode via the quick tile.
Disabling other routes to put individual apps to freeform.

Test: visually verified that freeform button is not visible when desktop
windowing prototype flag is enabled
Bug: 242906219

Change-Id: Ib1ce75969b67f30d82262927e2e4113fab2c4956