Remove LRU spam prevention, as it's breaking the LRU.

Return early to disable the LRU spam prevention implemented in
ProcessList.updateClientActivitiesOrderingLSP when the flag is
enabled, as it's breaking the LRU by spreading processes.

Bug: 421872956
Test: atest CtsAppTestCases:ServiceTest#testLruWhenSwitchingBetweenAppsInFreeFormWindows
Flag: com.android.server.am.remove_lru_spam_prevention
Change-Id: I577f7de9ed478cef618f62c6bdf9b182bd606e58