Guard more in color-modes.js (#38235)

Author: XhmikosR

site/static/docs/5.3/assets/js/color-modes.js

@@ -29,12 +29,12 @@
 
   const showActiveTheme = (theme, focus = false) => {
     const themeSwitcher = document.querySelector('#bd-theme')
+    const themeSwitcherText = document.querySelector('#bd-theme-text')
 
-    if (!themeSwitcher) {
+    if (!themeSwitcher || !themeSwitcherText) {
       return
     }
 
-    const themeSwitcherText = document.querySelector('#bd-theme-text')
     const activeThemeIcon = document.querySelector('.theme-icon-active use')
     const btnToActive = document.querySelector(`[data-bs-theme-value="${theme}"]`)
     const svgOfActiveBtn = btnToActive.querySelector('svg use').getAttribute('href')