fix: compilation errors when disable_xr=yes

Author: LanzaSchneider

scene/main/viewport.cpp

@@ -1118,7 +1118,7 @@ bool Viewport::_set_size(const Size2i &p_size, const Size2 &p_size_2d_override,
 	stretch_transform = stretch_transform_new;
 	font_oversampling = new_font_oversampling;
 
-#ifndef _3D_DISABLED
+#ifndef XR_DISABLED
 	if (!use_xr) {
 #endif
 
@@ -1128,7 +1128,7 @@ bool Viewport::_set_size(const Size2i &p_size, const Size2 &p_size_2d_override,
 			RS::get_singleton()->viewport_set_size(viewport, 0, 0);
 		}
 
-#ifndef _3D_DISABLED
+#ifndef XR_DISABLED
 	} // if (!use_xr)
 #endif