[UI] Fix easter egg prize receiving.

app/src/main/java/pl/szczodrzynski/edziennik/ui/modules/login/LoginEggsFragment.kt

@@ -95,9 +95,11 @@ class LoginEggsFragment : Fragment(), CoroutineScope {
                     anim.interpolator = AccelerateDecelerateInterpolator()
                     anim.duration = 10
                     anim.fillAfter = true
+                    activity.runOnUiThread {
                         activity.getRootView().startAnimation(anim)
                         nav.navigate(R.id.loginPrizeFragment, null, activity.navOptions)
                     }
+                }
             }, "EggInterface")
             loadUrl("https://szkolny.eu/game/runner.html")
             webViewClient = object : WebViewClient() {