Fix #108171: bpy.ops.uv.pack_islands crash

Originally caused by edc12436c6, the fix c4f39eab88 also had a mistake
unfortunately (double free of `UVPackIslandsData` since it already
called `pack_islands_freejob`).

Pull Request: https://projects.blender.org/blender/blender/pulls/109377

source/blender/editors/uvedit/uvedit_unwrap_ops.cc

@@ -1555,7 +1555,6 @@ static int pack_islands_exec(bContext *C, wmOperator *op)
   pack_islands_endjob(pid);
   pack_islands_freejob(pid);
 
-  MEM_freeN(pid);
   return OPERATOR_FINISHED;
 }