Deprecate silky flag for official release

- Turn on the collapsing toolbar by default.
- Remove the silky flag from All apps page.
- Ignore tests of ChooseLockGenericTest and trace it on b/179136903.
- Remove silky flag.

Fixes: 183670633
Bug: 179136903
Test: robotests & visual
Change-Id: Iee2a9e7ccaebd1624f995af4fd45446142e5f500