Update lib/rules/no-negated-v-if-condition.js

Co-authored-by: Flo Edelmann <git@flo-edelmann.de>

Author: waynzh

lib/rules/no-negated-v-if-condition.js

@@ -153,8 +153,9 @@ module.exports = {
  * @returns {string}
  */
  function getElementContent(element) {
- if (element.children.length === 0) return ''
- if (!element.endTag) return ''
+ if (element.children.length === 0 || !element.endTag) {
+ return ''
+ }
 
  const contentStart = element.startTag.range[1]
  const contentEnd = element.endTag.range[0]