fix: `preferCSSPageSize` error type (#38793)

fix: preferCSSPageSize error type

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Shelley Vohr <[email protected]>

lib/browser/api/web-contents.ts

@@ -317,7 +317,7 @@ WebContents.prototype.printToPDF = async function (options) {
 
   if (options.preferCSSPageSize !== undefined) {
     if (typeof options.preferCSSPageSize !== 'boolean') {
-      return Promise.reject(new Error('footerTemplate must be a String'));
+      return Promise.reject(new Error('preferCSSPageSize must be a Boolean'));
     }
     printSettings.preferCSSPageSize = options.preferCSSPageSize;
   }