Remove temporary `WMShellPipTests` now that test configurations have been updated

Bug: 301574363
Test: atest WMShellFlickerTestsPip1 WMShellFlickerTestsPip2 WMShellFlickerTestsPip3
Change-Id: I68ea59fd893dd9b2fbb59a8a1070626d5fc48708
1 file changed