[ui] Fixes double-namespace-query-param when getting versions (#24466)

ui/app/adapters/job.js

@@ -172,22 +172,8 @@ export default class JobAdapter extends WatchableNamespaceIDs {
   }
 
   getVersions(job, diffVersion) {
-    const url = addToPath(
-      this.urlForFindRecord(job.get('id'), 'job'),
-      '/versions'
-    );
-
-    const namespace = job.get('namespace.name') || 'default';
-
-    const query = {
-      namespace,
-      diffs: true,
-    };
-
-    if (diffVersion) {
-      query.diff_version = diffVersion;
-    }
-    return this.ajax(url, 'GET', { data: query });
+    let url = this.urlForVersions(job, diffVersion);
+    return this.ajax(url, 'GET');
   }
 
   /**
@@ -276,6 +262,17 @@ export default class JobAdapter extends WatchableNamespaceIDs {
     return result;
   }
 
+  urlForVersions(job, diffVersion) {
+    let url = this.urlForFindRecord(job.get('id'), 'job', null, 'versions');
+
+    let paramString = 'diffs=true';
+    if (diffVersion) {
+      paramString += `&diff_version=${diffVersion}`;
+    }
+    url = addToPath(url, '', paramString);
+    return url;
+  }
+
   urlForQuery(query, modelName, method) {
     let baseUrl = `/${this.namespace}/jobs/statuses`;
     if (method === 'POST' && query.index) {