Remove type check on pre reqs as MV flags do not evaluate correctly

Author: stephenmcconkey

featureflags/evaluations/evaluator.py

@@ -293,7 +293,8 @@ def _check_prerequisite(self, parent: FeatureConfig,
                 log.info('Pre requisite flag %s should have the variations %s',
                          config.feature, pqs.variations)
 
-                if variation.identifier not in pqs.variations:
+                if not isinstance(variation, Unset) and variation.identifier \
+                        not in pqs.variations:
                     return False
                 else:
                     return self._check_prerequisite(config, target)