Get bitmap from vector drawable in shortcuts

Phone icons aren't bitmap drawables anymore so convert the vector
into a bitmap for display.

Test: Manually verified:
  * Adding direct dial and message shortcuts don't crash the app
  * Appearance of the widgets is the same as before.

Bug: 34394590
Change-Id: I5cc056fe53ae6c5f2a0830f2f5d4d034cc7b4937