netebpfext - user mode mock for wfp - Looking up filter context should match on properties

netebpfext's user mode mock selects the first filter instead of using the filter properties to match the correct filter.

Start in the netebpfext user mode mock implementation and trace the code that looks up filter context. Verify how filter properties are represented and compared, then add or update the relevant tests so lookup selects the matching filter rather than the first one.

Written by the indexing model from the issue text.