Perform text classification when emulator sets clipboard.

This fixes an issue where clipboard clips coming from the emulator
host do not have text classification performed, resulting in the
clip being permanently in the CLAFFICATION_NOT_PERFORMED state.

Bug: 204085258
Test: build; use system image in emulator; manual copy and check
Test: atest ClipDescriptionTest
Test: atest ClipboardManagerTest
Change-Id: Ic89d6e87976ec75a7b9a55e2602619aa6e93ddce