Batching - GLES3 fix light pass modulates

The final_modulate was incorrectly being set in the uniform on light passes in GLES3 in situations where color was baked in the vertices. This was already correct in GLES2. This PR makes prevents setting final_modulate in this situation.

drivers/gles3/rasterizer_canvas_gles3.cpp

@@ -1493,7 +1493,11 @@ void RasterizerCanvasGLES3::render_joined_item(const BItemJoined &p_bij, RenderI
 		Light *light = r_ris.item_group_light;
 		bool light_used = false;
 		VS::CanvasLightMode mode = VS::CANVAS_LIGHT_MODE_ADD;
-		state.canvas_item_modulate = p_ci->final_modulate; // remove the canvas modulate
+
+		// we leave this set to 1, 1, 1, 1 if using software because the colors are baked into the vertices
+		if (p_bij.is_single_item()) {
+			state.canvas_item_modulate = p_ci->final_modulate; // remove the canvas modulate
+		}
 
 		while (light) {