Add machine_learning/allowlisted_app_functions_agents to WritableFlags

The flag is used to determine the valid agents that has the permission
to execute the AppFunction. Exemption request to have a non-boolen flag
is approved in b/421911013

Bug: 416661798
Flag: android.permission.flags.app_function_access_api_enabled
Test: Presubmit
Change-Id: I04b098a5e4d3b50d74babe706676f18f9729ee5f
1 file changed
tree: 4e9618c07af10a63f506fff762625b73eea9bbef
  1. aconfigd/
  2. aflags/
  3. apex/
  4. framework/
  5. service/
  6. OWNERS
  7. TEST_MAPPING