utils function remove_tag_from_h5m_file is untested

[shimwell]

I recall adding the remove_tag_from_h5m_file function with a plan to replace it with the tested https://github.com/svalinn/remove_dagmc_tags but have not gotten arround to it quite yet. Perhaps now is a good time to remove the whole function as the next release of DAGMC will be able to add graveyards automatically svalinn/DAGMC#714

[shimwell]

no longer included in the code