Resize dialogs when the configuration changes

Before this CL, system dialogs would not react to configuration changes,
which would cause weird UI issues when folding into a smaller screen.

This CL makes all SystemUIDialog's listen for configuration changes, and
resize their window accordingly.

Bug: 204042506
Test: Manual
Change-Id: I4cf1dbfff2a95c83ed3e240d165eae60660c429b