Fix "TypeError: groups is not iterable" in _disableAgreements

This fixes an issue by adding a undefined check to _disableAgreements
in addition to that we also add the check to _computeHideAgreementClass too.

Bug: Issue 12020
Change-Id: Icf444aa315d24b34b5bf1cd62173ae62f6b84931

polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.js

@@ -108,6 +108,7 @@
     },
 
     _disableAgreements(item, groups, signedAgreements) {
+      if (!groups) return false;
       for (const group of groups) {
         if ((item && item.auto_verify_group &&
             item.auto_verify_group.id === group.id) ||
@@ -131,6 +132,7 @@
     // if specified it returns 'hideAgreementsTextBox' which
     // then hides the text box and submit button.
     _computeHideAgreementClass(name, config) {
+      if (!config) return '';
       for (const key in config) {
         if (!config.hasOwnProperty(key)) { continue; }
         for (const prop in config[key]) {

polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_test.html

@@ -150,6 +150,9 @@ limitations under the License.
       // Not in the auto verify group, have signed agreement
       assert.isTrue(
           element._disableAgreements(auth3, groups, signedAgreements));
+      // Make sure the undefined check works
+      assert.isFalse(
+          element._disableAgreements(auth, undefined, signedAgreements));
     });
 
     test('_hideAgreements', () => {