Fixing testRecentAppsFling

Aka “SysUi: Recent App fling” aka “SysUI - Recent Apps Fling”.

The fix works both with and without quickstep.

With quickstep, it will keep failing until Launcher implements
pressRecentApps() to show the new overview. I’ve tested this with a
hacky way to show overview via injected swipe.

Bug: 72967764
Test: atest google/perf/jank/SystemUI/UbSystemUIJankTests:android.platform.systemui.tests.jank.SystemUiJankTests#testRecentAppsFling
Change-Id: I1fbef25fae647baee3c430481d756947011a4183