Use correct stack height when bypass enabled.

Also removes the 'getPulseStackHeight' method which didn't solve any of the issues it was added to solve, and only introduced an issue when expanding a pulse on bypass device.

Fixes: 194513502
Test: on bypass device, expand QS; validate that notifications do not disappear at the bottom.
Test: on bypass device, receive pulse; unlock via bypass; validate that pulse seamlessly transitions to hun.
Test: on bypass device, expand shade from lock screen; validate that notifications all fade in at once, rather than appearing in sequence.
Test: on bypass device, receive pulse; drag to expand it; validate that other notifications appear in sequence, rather than popping in all at once. (Note, this is non-ideal behavior which has always existed, not a regression.  ideally other notifications would fade in.)
Test: on non-bypass device, receive pulse; biometric unlock; validate that notifications smoothly animate to open shade.
Change-Id: I8d0968f5a8632bba6b1db5940b933ee53b2abb8a