Factor in userId for updateHotseatItemsFromRunningTasks

Test: onRecentTasksChanged_inDesktopMode_sameHotseatPackage_differentUser_isInShownTasks
Test: Pin personal Chrome, open work Chrome in desktop mode; ensure a
new work icon is created in the running apps section
Flag: com.android.window.flags.enable_desktop_windowing_taskbar_running_apps
Bug: 376818660

Change-Id: Ie5cf3ab8e839456e6bd774de8a4398835e790019