refactor(@angular/ssr): mark LINK_LOAD_SCRIPT_CONTENT as @PURE

This const is pure.

(cherry picked from commit f7c0a83)

Author: alan-agius4

packages/angular/ssr/src/utils/inline-critical-css.ts

@@ -32,8 +32,7 @@ const CSP_MEDIA_ATTR = 'ngCspMedia';
  * - Removes the event listener when all relevant `<link>` tags have been processed.
  * - Uses event capturing (the `true` parameter) since load events do not bubble up the DOM.
  */
-const LINK_LOAD_SCRIPT_CONTENT = `
-(() => {
+const LINK_LOAD_SCRIPT_CONTENT = /* @__PURE__ */ (() => `(() => {
   const CSP_MEDIA_ATTR = '${CSP_MEDIA_ATTR}';
   const documentElement = document.documentElement;
 
@@ -57,7 +56,7 @@ const LINK_LOAD_SCRIPT_CONTENT = `
   };
 
   documentElement.addEventListener('load', listener, true);
-})();`;
+})();`)();
 
 /** Partial representation of an `HTMLElement`. */
 interface PartialHTMLElement {