Update UI when errors within array change.

src/core_plugins/kibana/public/management/sections/indices/create_index_pattern_wizard/step_index_pattern/step_index_pattern.js

@@ -36,7 +36,7 @@ module.directive('stepIndexPattern', function () {
         // If the index pattern name is invalid, we should reflect that state in the list.
         scope.stepIndexPattern.updateList();
       });
-      scope.$watch('stepIndexPattern.indexPatternNameForm.$error', () => {
+      scope.$watchCollection('stepIndexPattern.indexPatternNameForm.$error', () => {
         // If we immediately replace the input with an invalid string, then only the form state
         // changes, but not the `indexPatternName` value, so we need to watch both.
         scope.stepIndexPattern.updateList();