Don't override oauth2_provider settings dict

Author: mvandenburgh

dandiapi/settings.py

@@ -202,8 +202,8 @@ def mutate_configuration(configuration: type[ComposedConfiguration]):
 
 
 class HerokuStagingConfiguration(HerokuProductionConfiguration):
-    # The staging configuration enables wildcards in OAuth redirect URIs in order
-    # to support Netlify deploy previews.
-    OAUTH2_PROVIDER = {
-        'ALLOW_URI_WILDCARDS': True,
-    }
+    @staticmethod
+    def mutate_configuration(configuration: type[ComposedConfiguration]):
+        # The staging configuration enables wildcards in OAuth redirect URIs in order
+        # to support Netlify deploy previews.
+        configuration.OAUTH2_PROVIDER['ALLOW_URI_WILDCARDS'] = True