Remove jank tracker from back panel

This fixes the following crash:

FATAL EXCEPTION: main
Process: com.android.systemui.tests, PID: 4072
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.os.Handler.post(java.lang.Runnable)' on a null object reference
       at com.android.internal.jank.InteractionJankMonitor.postEventLogToWorkerThread(InteractionJankMonitor.java:598)
       at com.android.internal.jank.InteractionJankMonitor.end(InteractionJankMonitor.java:383)
       at com.android.systemui.navigationbar.gestural.BackPanelController.updateArrowState(BackPanelController.kt:892)
       at com.android.systemui.navigationbar.gestural.BackPanelController.updateArrowState$default(BackPanelController.kt:880)
       at com.android.systemui.navigationbar.gestural.BackPanelController$onEndSetGoneStateListener$1.run(BackPanelController.kt:243)
       at android.os.Handler.handleCallback(Handler.java:959)
       at android.os.Handler.dispatchMessage(Handler.java:100)
       at android.os.Looper.loopOnce(Looper.java:232)
       at android.os.Looper.loop(Looper.java:317)
       at android.app.ActivityThread.main(ActivityThread.java:8524)
       at java.lang.reflect.Method.invoke(Native Method)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878)

Bug: 304583132
Bug: 304582856
Flag: ACONFIG com.android.systemui.edge_back_gesture_handler_thread DISABLED
Change-Id: Ib1e4c56111a908586b17b7225371317121909fce