exit early in renderContent() on empty template (#22979)

Part of #1187

Co-authored-by: Octomerger Bot <63058869+Octomerger@users.noreply.github.com>

Author: Peter Bengtsson

lib/render-content/renderContent.js

@@ -17,6 +17,9 @@ const inlineTagRegex = new RegExp(`\n?(</?${inlineTagString}>?)\n?`, 'gm')
 
 // parse multiple times because some templates contain more templates. :]
 async function renderContent(template = '', context = {}, options = {}) {
+  // If called with a falsy template, it can't ever become something
+  // when rendered. We can exit early to save some pointless work.
+  if (!template) return template
   try {
     // remove any newlines that precede html comments, then remove the comments
     if (template) {