fix JS error in interacive TOC

when no toc is available on the current page, an error would be thrown.
This is now fixed. When no toc is available the code in question is not  executed.

Also removed some unecessary JQuery

doxygen-awesome-interactive-toc.js

@@ -33,9 +33,9 @@ class DoxygenAwesomeInteractiveToc {
     static headers = []
 
     static init() {
-        $(function() {
-            $(document).ready(function() {
-                let toc = document.querySelector(".contents > .toc")
+        window.addEventListener("load", () => {
+            let toc = document.querySelector(".contents > .toc")
+            if(toc) {
                 toc.classList.add("interactive")
                 if(!DoxygenAwesomeInteractiveToc.hideMobileMenu) {
                     toc.classList.add("open")
@@ -46,7 +46,6 @@ class DoxygenAwesomeInteractiveToc {
                     } else {
                         toc.classList.add("open")
                     }
-
                 })
 
                 document.querySelectorAll(".contents > .toc > ul a").forEach((node) => {
@@ -61,7 +60,7 @@ class DoxygenAwesomeInteractiveToc {
                     })
                 })
                 DoxygenAwesomeInteractiveToc.update()
-            })
+            }
         })
     }