replace the URL only when needed

lib/single-file/single-file-core.js

@@ -722,8 +722,8 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 					stylesheetContent = stylesheetContent.replace(urlFunction, urlFunction.replace(resourceURL, new URL(resourceURL, baseURI).href));
 				} else {
 					if (resourceURL.startsWith(DATA_URI_PREFIX)) {
-						if (resourceURL.includes("<")) {
-							const escapedResourceURL = resourceURL.replace(/&/g, "&amp;").replace(/\u00a0/g, "&nbsp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
+						const escapedResourceURL = resourceURL.replace(/&/g, "&amp;").replace(/\u00a0/g, "&nbsp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
+						if (escapedResourceURL != resourceURL) {
 							stylesheetContent = stylesheetContent.replace(resourceURL, escapedResourceURL);
 						}
 					}