fix logout for auth0 (#1719)

* fix logout for auth0

the redirect from logout needs to be registered, and therefore cannot
be an arbitrary path in the server.  When the user logs out, they are
redirected to the index page

* no need to provide dataset to logout url

server/auth/auth_oauth.py

@@ -144,14 +144,12 @@ class AuthTypeOAuth(AuthTypeClientBase):
             @after_this_request
             def remove_cookie(response):
                 response.set_cookie(self.cookie_params["key"], "", expires=0)
-                self.update_response()
+                self.update_response(response)
                 return response
 
-        return_path = request.args.get("dataset", "")
-        return_to = f"{self.callback_base_url}/{return_path}"
-        params = {'returnTo' : return_to, 'client_id' : self.client_id}
+        params = {'returnTo' : self.callback_base_url, 'client_id' : self.client_id}
         response = redirect(self.client.api_base_url + '/v2/logout?' + urlencode(params))
-        self.update_response()
+        self.update_response(response)
         return response
 
     def callback(self):
@@ -186,10 +184,7 @@ class AuthTypeOAuth(AuthTypeClientBase):
 
     def get_logout_url(self, data_adaptor):
         """Return the url for the logout route"""
-        if current_app.app_config.is_multi_dataset():
-            return f"/logout?dataset={data_adaptor.uri_path}"
-        else:
-            return "/logout"
+        return "/logout"
 
     def get_token(self):
         """Function to return the token"""