Make sure ThemeConfig is non-null when loading resources

When the device boots into safemode, the theme config will end up
being null and we need to check that prior to using it to retrieve
resources for the StatusBarIconView

This fixes CYAN-5009

Change-Id: I1a90bc9f9c65cb41a6e58947bbd1b6d7728a952b
Merge "Make sure ThemeConfig is non-null when loading resources" into kk4.4