Fixes #1223: Hide action bar on crash fragment

app/src/main/java/org/mozilla/fenix/crashes/CrashReporterFragment.kt

@@ -9,6 +9,7 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.TextView
+import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import androidx.navigation.Navigation
 import kotlinx.android.synthetic.main.fragment_crash_reporter.*
@@ -48,6 +49,11 @@ class CrashReporterFragment : Fragment() {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        (activity as AppCompatActivity).supportActionBar?.hide()
+    }
+
     fun navigateHome(fromView: View) {
         val directions = CrashReporterFragmentDirections.actionCrashReporterFragmentToHomeFragment()
         Navigation.findNavController(fromView).navigate(directions)