TextClassifier API updates.

1. Wraps TC queries in Request objects
2. Adds create/destroyTextClassificationSession system APIs
3. Adds the session Ids to system API calls
4. Change setSignature() to setId() on result objects
5. Plumbing to make the API updates work as things currently work
6. Hide Linkify.addLinksAsync APIs

Bug: 74461129

Test: bit FrameworksCoreTests:android.view.textclassifier.TextClassificationManagerTest
Test: bit CtsViewTestCases:android.view.textclassifier.cts.TextClassificationManagerTest
Test: bit CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: bit FrameworksCoreTests:android.widget.TextViewActivityTest
Test: bit FrameworksCoreTests:android.view.textclassifier.TextClassificationTest
Test: bit FrameworksCoreTests:android.view.textclassifier.TextSelectionTest
Test: bit FrameworksCoreTests:android.view.textclassifier.TextLinksTest

Change-Id: I933ada8b37ef9893331a265e3b4fc08e043f1029