Add ValidatedAttributionSourceState

Add type which encapsulates a validated attribution source, either via
binder context, or if it is passed from a trusted source.

This type will be used by the controller for permission validation.

Test: atest audiopermissioncontroller_test --host
Fixes: 259493676
Bug: 338089555
Flag: EXEMPT safe, adding utilities
Change-Id: I80af36b4b766b7c876f3d7cdb50257dc4d1c7dcd