FIX: Admin user fields weren't showing errors

Also updated it to remove deprecations and item controller

app/assets/javascripts/admin/components/admin-user-field-item.js.es6

@@ -0,0 +1,68 @@
+import { bufferedProperty } from 'discourse/mixins/buffered-content';
+import UserField from 'admin/models/user-field';
+import { popupAjaxError } from 'discourse/lib/ajax-error';
+
+export default Ember.Component.extend(bufferedProperty('userField'), {
+  editing: Ember.computed.empty('userField.id'),
+  classNameBindings: [':user-field'],
+
+  _focusOnEdit: function() {
+    if (this.get('editing')) {
+      Ember.run.scheduleOnce('afterRender', this, '_focusName');
+    }
+  }.observes('editing').on('didInsertElement'),
+
+  _focusName: function() {
+    $('.user-field-name').select();
+  },
+
+  fieldName: function() {
+    return UserField.fieldTypeById(this.get('userField.field_type')).get('name');
+  }.property('userField.field_type'),
+
+  flags: function() {
+    const ret = [];
+    if (this.get('userField.editable')) {
+      ret.push(I18n.t('admin.user_fields.editable.enabled'));
+    }
+    if (this.get('userField.required')) {
+      ret.push(I18n.t('admin.user_fields.required.enabled'));
+    }
+    if (this.get('userField.show_on_profile')) {
+      ret.push(I18n.t('admin.user_fields.show_on_profile.enabled'));
+    }
+
+    return ret.join(', ');
+  }.property('userField.editable', 'userField.required', 'userField.show_on_profile'),
+
+  actions: {
+    save: function() {
+      const self = this;
+      const attrs = this.get('buffered').getProperties('name', 'description', 'field_type', 'editable', 'required', 'show_on_profile');
+
+      this.get('userField').save(attrs).then(function(res) {
+        self.set('userField.id', res.user_field.id);
+        self.set('editing', false);
+        self.commitBuffer();
+      }).catch(popupAjaxError);
+    },
+
+    edit: function() {
+      this.set('editing', true);
+    },
+
+    destroy: function() {
+      this.sendAction('destroyAction', this.get('userField'));
+    },
+
+    cancel: function() {
+      const id = this.get('userField.id');
+      if (Ember.isEmpty(id)) {
+        this.sendAction('destroyAction', this.get('userField'));
+      } else {
+        this.rollbackBuffer();
+        this.set('editing', false);
+      }
+    }
+  }
+});