fix updating a collection if you don't have access to all the cases

atlas/forms.py

@@ -464,10 +464,10 @@ class CaseSeriesForm(ModelForm):
 
 
 class CaseCollectionCaseForm(ModelForm):
-    def __init__(self, *args, user, **kwargs):
+    def __init__(self, *args, user, collection, **kwargs):
         super(CaseCollectionCaseForm, self).__init__(*args, **kwargs)
 
-        queryset = get_cases_available_to_user(user)
+        queryset = get_cases_available_to_user(user, collection=collection)
 
         self.fields["case"] = ModelChoiceField(
             required=False,