Make is less likely to ignore PIN tap events

The PIN area can be dragged vertically to retry face auth,
the touch slope was already scaled up to avoid accidental
drags but some users still reported that taps were being
ignored. This CL increases the touch slope size.

Fixes: 140030986
Bug: 141873371
Test: manual
Change-Id: I8db78942797f2c44caf9c9bdc0ec693e6c6a65f9