Prevent duplicated registration of OnComputeInternalInsetsListener

OnComputeInternalInsetsListener is added when initViews is called,
and initViews is called by onCreate and onConfigurationChanged.
But it is removed only by onDestroy.
Therefore listeners are accumulated and it results performance issue.
So before adding, remove mInsetListener that was previously added.

Change-Id: I494d3f1875613d73d3f9b8e2af286b5800f03196