Removes collections.abc.Iterable superclass

Per @gcmoreira this is the correct fix vs the one previously proposed,
since self.vol.member_name cannot be used as the member name to
iterate this type.

volatility3/framework/symbols/linux/extensions/__init__.py

@@ -1004,7 +1004,7 @@ def __iter__(self) -> Iterator[interfaces.objects.ObjectInterface]:
         return self.to_list(self.vol.parent.vol.type_name, self.vol.member_name)
 
 
-class hlist_head(objects.StructType, collections.abc.Iterable):
+class hlist_head(objects.StructType):
     def to_list(
         self,
         symbol_type: str,
@@ -1037,9 +1037,6 @@ def to_list(
 
             current = current.next
 
-    def __iter__(self) -> Iterator[interfaces.objects.ObjectInterface]:
-        return self.to_list(self.vol.parent.vol.type_name, self.vol.member_name)
-
 
 class files_struct(objects.StructType):
     def get_fds(self) -> interfaces.objects.ObjectInterface: