Fix AAOS SystemUI Presubmit tests that are breaking.

Due to the newly added check in SystemBarConfig, tests can fail
erroneously when testing behavior of when either top or bottom system
bar is not enabled.

Bug: 162599873
Bug: 165808744
Test: atest carsysui-presubmit --include-subdir passing. (5/5)
Change-Id: Ife2ac4e746006c39eaf46cd0328c1639149891b2