misc: always use a fresh copy of parameters (#17173)

(this is required for tests)

combo/data/models.py

@@ -1023,7 +1023,7 @@ class ConfigJsonCell(JsonCellBase):
         return config_form_class
 
     def get_cell_extra_context(self, context, **kwargs):
-        context.update(self.parameters) # early push for templated URLs
+        context.update(copy.copy(self.parameters)) # early push for templated URLs
         ctx = super(ConfigJsonCell, self).get_cell_extra_context(context, **kwargs)
         ctx['parameters'] = self.parameters
         ctx.update(self.parameters)