feat: get user scim v2 endpoint (#9161)

# Which Problems Are Solved
- Adds support for the get user SCIM v2 endpoint

# How the Problems Are Solved
- Adds support for the get user SCIM v2 endpoint under `GET
/scim/v2/{orgID}/Users/{id}`

# Additional Context
Part of #8140
Replaces https://github.com/zitadel/zitadel/pull/9154 as requested by
the maintainers, discussions see
https://github.com/zitadel/zitadel/pull/9154.

internal/api/scim/server.go

@@ -54,6 +54,7 @@ func mapResource[T sresources.ResourceHolder](router *mux.Router, mw zhttp_middl
 	resourceRouter := router.PathPrefix("/" + path.Join(zhttp.OrgIdInPathVariable, string(handler.ResourceNamePlural()))).Subrouter()
 
 	resourceRouter.Handle("", mw(handleResourceCreatedResponse(adapter.Create))).Methods(http.MethodPost)
+	resourceRouter.Handle("/{id}", mw(handleResourceResponse(adapter.Get))).Methods(http.MethodGet)
 	resourceRouter.Handle("/{id}", mw(handleEmptyResponse(adapter.Delete))).Methods(http.MethodDelete)
 }
 
@@ -74,6 +75,22 @@ func handleResourceCreatedResponse[T sresources.ResourceHolder](next func(*http.
 	}
 }
 
+func handleResourceResponse[T sresources.ResourceHolder](next func(*http.Request) (T, error)) zhttp_middlware.HandlerFuncWithError {
+	return func(w http.ResponseWriter, r *http.Request) error {
+		entity, err := next(r)
+		if err != nil {
+			return err
+		}
+
+		resource := entity.GetResource()
+		w.Header().Set(zhttp.ContentLocation, resource.Meta.Location)
+
+		err = json.NewEncoder(w).Encode(entity)
+		logging.OnError(err).Warn("scim json response encoding failed")
+		return nil
+	}
+}
+
 func handleEmptyResponse(next func(*http.Request) error) zhttp_middlware.HandlerFuncWithError {
 	return func(w http.ResponseWriter, r *http.Request) error {
 		err := next(r)