refactor: Move registry.get_methods() call to separate method, to all…

…ow customization

Refs jazzband#533

two_factor/views/core.py

@@ -482,7 +482,7 @@ def get_form_list(self):
         """
         form_list = super().get_form_list()
 
-        available_methods = registry.get_methods()
+        available_methods = self.get_available_methods()
         if len(available_methods) == 1:
             form_list.pop('method', None)
             method_key = available_methods[0].code
@@ -497,6 +497,9 @@ def get_form_list(self):
             form_list['validation'] = DeviceValidationForm
         return form_list
 
+    def get_available_methods(self):
+        return registry.get_methods()
+
     def render_next_step(self, form, **kwargs):
         """
         In the validation step, ask the device to generate a challenge.