Change <vibration> to <vibration-effect>

<vibration> could later be used as a generic tag for different
representations of vibrations, other than VibrationEffects. Thus, this
change changes the tag used to serialize VibrationEffects from
<vibration> to <vibration-effect>.

Contents of change is under the `enable_vibration_serialization_apis`
flag, so no new flag is created as this CL is only a simple rename.

Bug: 297296718
Test: unit tests, presubmit

Change-Id: I8c7fb12ad3602ccc213b59b36db1e733c4e2b396