Make dimens in StatusBarIconView resources

Now the expected size and desired size of System Icons can be overlaid.
Resources as part of core, so they can be overlaid by Car.

Also, makes sure that maybeUpdateIconScaleDimens is the one called to
sort out what updateIconScaleXXXX should be called.

Test: visual, using icons that are not 17dp
Fixes: 132354163
Change-Id: I902050d4b3c44587a023614f738ebad1d857b8bf