Standardize flag usages in DevicePolicyManager

Flags should be referenced as Flags.foo() in conditionals
while as @FlaggedApi(FLAG_FOO) in API flagging. This is to
ensure their nature as feature flags is clear.

Bug: 325597690
Test: builds
Change-Id: I082715cc3047d8c508641c1d9a0c3b4b9c3a9d15
10 files changed