Fix injection crash in UI tests on pre Android 11

Corona-Warn-App/src/androidTest/java/testhelpers/TestApplication.kt

@@ -30,12 +30,14 @@ class TestApplication : Application(), HasAndroidInjector {
 
     private fun setupActivityHook() {
         registerActivityLifecycleCallbacks(object : ActivityLifecycleCallbacks {
-            override fun onActivityPreCreated(activity: Activity, savedInstanceState: Bundle?) {
+            override fun onActivityPreCreated(activity: Activity, savedInstanceState: Bundle?) = Unit
+
+            override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) {
+                Timber.d("onActivityCreated")
                 setupFragmentHook(activity)
+                Timber.d("FragmentHook injection is called")
             }
 
-            override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) = Unit
-
             override fun onActivityStarted(activity: Activity) = Unit
 
             override fun onActivityResumed(activity: Activity) = Unit