Add calling package name to TC requests.

- This is only set by the SystemTextClassifier.
- The system verifies that the package name is correct before
  passing the request to the TCS. Note that the system is the
  only direct client of the TCS.
- Sets package name to context.getOpPackageName(). See b/119921159
- Also adds an extra to a TextLink object.

Bug: 118690735
Bug: 119921159
Test: atest frameworks/base/core/tests/coretests/src/android/view/textclassifier
Change-Id: I1ac0fa421cd0f26e580a8e0768c3819a731bb471