[Fix] Fix in lightmapper where a material lightmap would be incorrect…

…ly released during baking (playcanvas#7005)

Co-authored-by: Martin Valigursky <[email protected]>

src/framework/lightmapper/lightmapper.js

@@ -971,7 +971,7 @@ class Lightmapper {
                 m.mask = MASK_BAKE; // only affected by LM lights
 
                 // patch material
-                m.setRealtimeLightmap(MeshInstance.lightmapParamNames[0], m.material.lightMap ? m.material.lightMap : this.blackTex);
+                m.setRealtimeLightmap(MeshInstance.lightmapParamNames[0], this.blackTex);
                 m.setRealtimeLightmap(MeshInstance.lightmapParamNames[1], this.blackTex);
             }
         }