Fixes #291 - less strict filter check
Fixes #291 - less strict filter check

Instead of checking the field contents (we’ve no idea what the user
wants to test for) we just check that they’re using it.

fede91it/crud,Laravel-Backpack/crud,Laravel-Backpack/crud,Laravel-Backpack/crud,Laravel-Backpack/crud,fede91it/crud,fede91it/crud,fede91it/crud