Fix mobile icon in shade header being too large on connected displays

There are two parts to this fix:
1. The shade moves between displays, and when it happens, a
   configuration shade is triggered.
   ModernStatusBarMobileView was not updating its dimensions after this
   configuration change.
2. ModernStatusBarMobileView was using a custom Context, with a mcc and
   mnc override. The way it was done, was with a ThemeContextWrapper and
   a Configuration override. The Configuration used for the override was
   based on the base Configuration + MMC and MNC.
   This was not working together with our display aware Context, which
   gets updated whenever the shade moves between displays. With this
   approach, it would always have the display metrics of the
   initial display, and not get updated.
   The solution here is to create an empty Configuration object for the
   override, and only set the MCC and MNC. This way only MCC and MNC are
   used for the override.

Bug: 412409667
Test: ModernStatusBarMobileViewTest
Test: MobileContextProviderTest
Test: Demo mode - Mobile data and MCC and MNC values set
Flag: com.android.systemui.fix_shade_header_wrong_icon_size
Change-Id: I4e92cc8fea62403bb1b0a8e469f1b2d634aa2c15