message: Better help text when editing username.
diff: <control-errors></control-errors>
  <p class="help-block">
  - {{ ::Environment.baseUrl }}/@{{ formModel.username }}
  + <span translate>Profile URL</span> <code>{{ ::Environment.baseUrl }}/@<strong>{{ formModel.username || '_' }}</strong></code>
  </p>
  <div gj-expand-when="formModel.username != baseModel.username">
  </div>
  </form-group>
  -
  <div class="form-group" ng-if="usernameTimeLeft">
  <label class="control-label">{{ ::'dash.profile.edit.username_label' | translate }}</label>
  <p class="form-control-static">{{ ::formModel.username }}</p>
  