Merge branch 'improve-scim-code-quality' into 'master'

Refactor scim to improve code quality

See merge request gitlab-org/gitlab!25773

ee/lib/api/scim.rb

@@ -45,16 +45,18 @@ module API
           render_scim_error(EE::Gitlab::Scim::Conflict, message)
         end
 
+        def check_access_to_group!(group)
+          token = Doorkeeper::OAuth::Token.from_request(current_request, *Doorkeeper.configuration.access_token_methods)
+
+          unauthorized! unless token && ScimOauthAccessToken.token_matches_for_group?(token, group)
+        end
+
         def find_and_authenticate_group!(group_path)
           group = find_group(group_path)
 
           scim_not_found!(message: "Group #{group_path} not found") unless group
 
-          token = Doorkeeper::OAuth::Token.from_request(current_request, *Doorkeeper.configuration.access_token_methods)
-          unauthorized! unless token
-
-          scim_token = ScimOauthAccessToken.token_matches_for_group?(token, group)
-          unauthorized! unless scim_token
+          check_access_to_group!(group)
 
           group
         end