[Workspace] delete useless code

Signed-off-by: yubonluo <yubonluo@amazon.com>

src/plugins/workspace/opensearch_dashboards.json

@@ -7,6 +7,6 @@
     "savedObjects",
     "opensearchDashboardsReact"
   ],
-  "optionalPlugins": ["savedObjectsManagement", "management"],
+  "optionalPlugins": ["savedObjectsManagement","management"],
   "requiredBundles": ["opensearchDashboardsReact"]
 }