Removing GHBM logic from codebase since it has been replaced by LHBM.
This will simplify the current implementation, and assist with future
refactors and the transition to Kotlin.
Fixes: 227229729
Test: atest UdfpsViewTest
Test: atest DisplayModeDirectorTest
Change-Id: I0d1e7ffb610154f4d56afab8385883a0389f89db