Account for compat scaling in NoticationTemplateTest-s

Make sure to pass DisplayMetrics from the current Context when
creating Bitmaps, so that they get the actual density instead of the
default one.

Bug: 198742691
Test: atest CtsLegacyNotification30TestCases
Change-Id: I93f0996e198f71345d8de457aa62d3f8310b5316
1 file changed