clean(mpa): correct mimetype for export results
clean(mpa): correct mimetype for export results

bmesuere/uni-test,unipept/unipept,bmesuere/uni-test,unipept/unipept,bmesuere/uni-test,bmesuere/uni-test,unipept/unipept,unipept/unipept,bmesuere/uni-test,unipept/unipept