Keep rendering context window size in sync when resizing

On X11 we rely on ConfigureNotify event to update rendering context
window size, but we don't get such event when resizing
programmatically, only when done "manually" by resizing the window
etc.

platform/linuxbsd/display_server_x11.cpp

@@ -1729,6 +1729,18 @@ void DisplayServerX11::window_set_size(const Size2i p_size, WindowID p_window) {
 
 		usleep(10000);
 	}
+
+	// Keep rendering context window size in sync
+#if defined(VULKAN_ENABLED)
+	if (context_vulkan) {
+		context_vulkan->window_resize(p_window, xwa.width, xwa.height);
+	}
+#endif
+#if defined(GLES3_ENABLED)
+	if (gl_manager) {
+		gl_manager->window_resize(p_window, xwa.width, xwa.height);
+	}
+#endif
 }
 
 Size2i DisplayServerX11::window_get_size(WindowID p_window) const {