fix: correct filter conditions to use strict inequalities

[tobiasploetz]

Such that the actual filtering aligns with filter definitions, e.g.

--additional_filters 'ALA_fraction<0.3' 'filter_rmsd_design<2.5'

[tobiasploetz]

I think this breaks some existing filters that assume >= and <= to be used. A better way forward would be to add an equality flag to the filter dictionaries, and let users also define additional filters like metric<=threshold