Add viewport to the other SceneData struct.

This was missed in #12288.

drivers/gles3/shaders/scene.glsl

@@ -665,6 +665,7 @@ layout(std140) uniform SceneData {
 	highp float shadow_dual_paraboloid_render_zfar;
 	highp float shadow_dual_paraboloid_render_side;
 
+	highp vec2 viewport_size;
 	highp vec2 screen_pixel_size;
 	highp vec2 shadow_atlas_pixel_size;
 	highp vec2 directional_shadow_pixel_size;