Remove SAFE_MODE_ENABLED's custom waveform vibration config

We can now customize the vibration of any haptic feedback via an XML
schema, so there is no need to keep SAFE_MODE_ENABLED's one-off
solution.

Bug: 418082619
Test: HapticFeedbackVibrationProviderTest
Flag: EXEMPT cleanup only
Change-Id: I079b7542370e2d1761914c33e77064e968474ca8