Fix WINDOW_EVENT_FOCUS_IN for popups on Windows

On Windows, WINDOW_EVENT_FOCUS_IN was never sent by the display server
for popups, because WM_ACTIVATE events are received during the call to
_update_window_style, which happened before the callbacks were set.

This was causing some issues with the way Popup is now handling closing on
parent focus.

Now _update_window_style is only called during show_window, after Window
initialized callbacks.

platform/windows/display_server_windows.cpp

@@ -493,14 +493,16 @@ DisplayServer::WindowID DisplayServerWindows::create_sub_window(WindowMode p_mod
 		wd.no_focus = true;
 	}
 
-	_update_window_style(window_id);
-
 	return window_id;
 }
 
 void DisplayServerWindows::show_window(WindowID p_id) {
 	WindowData &wd = windows[p_id];
 
+	if (p_id != MAIN_WINDOW_ID) {
+		_update_window_style(p_id);
+	}
+
 	ShowWindow(wd.hWnd, wd.no_focus ? SW_SHOWNOACTIVATE : SW_SHOW); // Show The Window
 	if (!wd.no_focus) {
 		SetForegroundWindow(wd.hWnd); // Slightly Higher Priority

scene/main/window.cpp

@@ -246,6 +246,8 @@ void Window::_make_window() {
 		}
 	}
 
+	_update_window_callbacks();
+
 	RS::get_singleton()->viewport_set_update_mode(get_viewport_rid(), RS::VIEWPORT_UPDATE_WHEN_VISIBLE);
 	DisplayServer::get_singleton()->show_window(window_id);
 }
@@ -379,7 +381,6 @@ void Window::set_visible(bool p_visible) {
 		}
 		if (p_visible && window_id == DisplayServer::INVALID_WINDOW_ID) {
 			_make_window();
-			_update_window_callbacks();
 		}
 	} else {
 		if (visible) {
@@ -738,7 +739,6 @@ void Window::_notification(int p_what) {
 				//create
 				if (visible) {
 					_make_window();
-					_update_window_callbacks();
 				}
 			}
 		}