feat: Add custom attribute table (#2929)

app/javascript/dashboard/api/attributes.js

@@ -1,9 +1,14 @@
+/* global axios */
 import ApiClient from './ApiClient';
 
 class AttributeAPI extends ApiClient {
   constructor() {
     super('custom_attribute_definitions', { accountScoped: true });
   }
+
+  getAttributesByModel(modelId) {
+    return axios.get(`${this.url}?attribute_model=${modelId}`);
+  }
 }
 
 export default new AttributeAPI();