Revert "InCallUI: Disable Back button on Non-intursive InCall Card"

This reverts commit e04b513d64699472e8d0f48ea1728f9f249da652.

Change-Id: I39646de95b2a08366f0769617edf22d677e5370f
Merge "Revert "InCallUI: Disable Back button on Non-intursive InCall Card"" into kk4.4