Properly handle orientation change for alarm display/edit.

Normally activities are destroyed and re-created during an orientation change.
But many of the existing alarm activities have configChanges set in the
AndroidManifest file. This causes the framework to re-size instead of
re-creating the activity on orientation change. In turn, this prevents the
properly layouts and styles from being applied even though there are size
specific resources.

This caused a problem where the dialogs were too big after rotating from
portrait to landscape. Fixed the problem by removing configChanges and properly
handling orientation changes.

Bug: 7201797
Change-Id: I03ab20ce416db0bb8aeb0500dad2a08e7d015b52