Fix regression with defaultDisplay adjustments

ag/1542219 introduced a regression where if the display was the default
display, the configuration would still be adjusted as if it were
a non-default display. This fixes that logic to only adjust the
configuration if the display is non-default.

Bug:32133693
Test: cts-tradefed run cts --module CtsServicesHostTestCases --test android.server.cts.ActivityManagerAppConfigurationTests#testConfigurationUpdatesWhenRotatingToSideFromDocked
Change-Id: Ib2fda8c1651609efa9d20b3e2dace8a122864916