Made permission privileged to grant access to ExtServices

To enable OTP detection, ExtServices requires the ACCESS_TEXT_CLASSIFIER_BY_TYPE permission to access specific TextClassifier. Because ExtServices cannot utilize the role, the permission is being added as privileged to allow its granting.

Bug: 377229653
Bug: 388899782
Test: atest FrameworksCoreTests:TextClassificationManagerTest CtsTextClassifierTestCases:TextClassificationManagerTest CtsPermissionPolicyTestCases:PermissionPolicyTest
Flag: android.permission.flags.text_classifier_choice_api_enabled

Change-Id: I606227245a6c80f5717df92bfd3760f21ee11d11