NullPointerException in AccServ.onAccessibilityEvent when pressing home button

[Meems33]

Describe the bug
NPE in AccServ.onAccessibilityEvent when package context for an accessibility event is null

To Reproduce
Steps to reproduce the behaviour:

1. Hit home button
2. Error pops up in notification bar (sometimes)

Expected behaviour
No errors :)

Launcher Hijack Version and Device
4.0.3
Fire HD 10 9th gen

Logs

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.Object.equals(java.lang.Object)' on a null object reference
    at com.baronkiko.launcherhijack.AccServ.onAccessibilityEvent(AccServ.java:31)
    at android.accessibilityservice.AccessibilityService$2.onAccessibilityEvent(AccessibilityService.java:1538)
    at android.accessibilityservice.AccessibilityService$IAccessibilityServiceClientWrapper.executeMessage(AccessibilityService.java:1724)
    at com.android.internal.os.HandlerCaller$MyHandler.handleMessage(HandlerCaller.java:37)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:193)
    at android.app.ActivityThread.main(ActivityThread.java:6734)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Additional context
Fixed with #73