Fix OIDC callback query params (#15378)

* Fix OIDC callback query params

- Value of namespace was getting stripped from the state query param
- Used native URL search param api to fetch the values

* Add changelog

* Remove unnecessary check for url encoding

* Extract ns value and pass as namespace param

* Update changelog

changelog/15378.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+ui: Allow namespace param to be parsed from state queryParam
+```

ui/app/routes/vault/cluster/oidc-callback.js

@@ -6,11 +6,28 @@ export default Route.extend({
     // left blank so we render the template immediately
   },
   afterModel() {
-    let { auth_path: path, code, state } = this.paramsFor(this.routeName);
+    const queryString = decodeURIComponent(window.location.search);
+    // Since state param can also contain namespace, fetch the values using native url api.
+    // For instance, state params value can be state=st_123456,ns=d4fq
+    // Ember paramsFor used to strip out the value after the "=" sign. In short ns value was not being passed along.
+    let urlParams = new URLSearchParams(queryString);
+    let state = urlParams.get('state'),
+      code = urlParams.get('code'),
+      ns;
+    if (state.includes(',ns=')) {
+      let arrayParams = state.split(',ns=');
+      state = arrayParams[0];
+      ns = arrayParams[1];
+    }
+    let { auth_path: path } = this.paramsFor(this.routeName);
     let { namespaceQueryParam: namespace } = this.paramsFor('vault.cluster');
     path = window.decodeURIComponent(path);
     const source = 'oidc-callback'; // required by event listener in auth-jwt component
     let queryParams = { source, namespace, path, code, state };
+    // If state had ns value, send it as part of namespace param
+    if (ns) {
+      queryParams.namespace = ns;
+    }
     window.opener.postMessage(queryParams, window.origin);
   },
   setupController(controller) {