Add deletion of the mol form db to the lipid test

Author: kheal

tests/test_wf_lipidomics.py

@@ -131,6 +131,7 @@ def test_lipidomics_workflow():
     # Perform a molecular search on a few of the mass features
     mol_form_search = SearchMolecularFormulasLC(myLCMSobj)
     mol_form_search.run_mass_feature_search()
+    mol_form_search.delete_db()
 
     # Check results of molecular search
     assert myLCMSobj.mass_features[0].ms1_peak[0].string == "C20 H30 O2"