Update AppSearch visibility for EXECUTE_APP_FUNCTIONS permission

The caller must also be a valid aganet to have visibility to the
documents that requires EXECUTE_APP_FUNCTIONS permission.

This align with the new EXECUTE_APP_FUNCTIONS permission requirement.

Flag: com.android.appsearch.flags.enable_app_function_agent_allowlist_check
Bug: 420892441
Test: atest AppSearchServicesTests
Change-Id: I79324ca9f9c388777bcf1efcaac0d9187ac74256
6 files changed