fix(fix opening sidebar direct through url): Check if leafletBottomContainer is null
fix(fix opening sidebar direct through url): Check if leafletBottomContainer is null

All direct links that open the sidebar with information are broken on mobile devices because
leafletBottomContainer is null during resolving the states and in the calling stack of the
controllers.

fix #253

sensebox/OpenSenseMap,mpfeil/OpenSenseMap,mpfeil/OpenSenseMap,sensebox/OpenSenseMap