Make each setting conditionally available based on touchpad or mouse
connected to device.
Bug: 269100659
Test: TrackpadBottomPreferenceControllerTest
Test: TrackpadReverseScrollingPreferenceControllerTest
Test: TrackpadTapToClickPreferenceControllerTest
Test: TrackpadSettingsControllerTest
Flag: android.view.flags.enable_vector_cursor_a11y_settings
Change-Id: I601c29e20d69227779481c0a491256e36cfd268f
Bug: 321978150
Bug: 324058706
Test: $ m statsd_testdrive
$ ./out/host/linux-x86/bin/statsd_testdrive -e 97
Then toggle the setting, press Enter in the terminal, and check
the new actions are logged
Change-Id: I55b7cc3377e7b27e9570f3f1b79c1f300d5d5686
Screenshot: go/ag-26012379-screenshot
Bug: 321978150
Bug: 324058706
Test: with the flag disabled, check the new entry doesn't appear
Test: with the flag enabled, toggle the setting and check that it
enables and disables tap dragging (tapping then immediately putting
your finger back on the touchpad and moving it)
Test: with the flag enabled, check the setting appears in search results
Test: atest SettingsRoboTests:com.android.settings.inputmethod
Change-Id: Iccfbe842ff655ea295edc764cfc400709948df7d
