Remove dream-specific flag check from posturing interactor

The posture signal can be used either for dreams or for glanceable hub.
The interactor shouldn't check these flags, but rather they should be
checked at each individual call site.

The dream code already checks the flag before it forwards the posturing
result to dreams, and glanceable hub only activates posturing when the
v2 flag is enabled.

Flag: android.service.dreams.allow_dream_when_postured
Test: atest PosturingInteractorTest
Test: atest CommunalSettingsInteractorTest
Test: atest CommunalSettingsRepositoryTest
Fixes: 404149658
Change-Id: I2f1b10c61e70331f5801ba1e70141e785fb456f2