Create basic test case and instrumented field classification service for testing field classification service

Test flow: open login activity which will trigger field classification request on
framework. Then framework calls onFieldClassificationRequest() on remote
classification service. The test case first assert the
fieldClassfiicationRequest is sent and then assert there is no unhandled
field classification request after.

The Instrumented Field Classification Service mimic the behavior of the real field classification service. Testcase needs to call
enablePccDetectionSerive() to set the instrumentedFieldClassification
Service as the temporary field classification service.

Bug: b/266473823
Test: atest android.autofillservice.cts.servicebehavior.PccFieldClassificationTest

Change-Id: I0d8aa3dca3c067bf97de08774511b72822591220
6 files changed