Remove temp GAIA education screen from PS setup code

With this change the temp GAIA education screen is removed from private
space setup code and adds a new loading screen with "Just a sec" title
in the activity while the gms intent in launched to fix blank screen issue.

Screenrecording link:
b/336822960#comment7

Bug: 336822960
Test: Manual
Change-Id: I9ee41835b39c194fefb970321b7a9d5a30f87306

src/com/android/settings/privatespace/SetupPreFinishDelayFragment.java

@@ -92,7 +92,7 @@ public class SetupPreFinishDelayFragment extends InstrumentedFragment {
             @Nullable Bundle savedInstanceState) {
         GlifLayout rootView =
                 (GlifLayout)
-                        inflater.inflate(R.layout.private_space_pre_finish_delay, container, false);
+                        inflater.inflate(R.layout.private_space_wait_screen, container, false);
         OnBackPressedCallback callback =
                 new OnBackPressedCallback(true /* enabled by default */) {
                     @Override