[fenix] Closes https://github.com/mozilla-mobile/fenix/issues/784 - After session timeout, pop everything to home

app/src/main/java/org/mozilla/fenix/HomeActivity.kt

@@ -65,6 +65,10 @@ open class HomeActivity : AppCompatActivity() {
 
     override fun onResume() {
         super.onResume()
+        // There is no session, or it has timed out; we should pop everything to home
+        if (components.core.sessionStorage.current() == null) {
+            navHost.navController.popBackStack(R.id.homeFragment, false)
+        }
         components.analytics.metrics.track(Event.OpenedApp)
     }