fix: simplify acquisition of form element

When rendering the app for the first time, a brittle manual tree walk is used. Instead, query for the form element directly (as we expect there to only be one). This ensures that other minor modifications to the app don't break form acquisition.

src/scripts/module.ts

@@ -62,10 +62,7 @@ Hooks.on("renderInvitationLinks", (links:InvitationLinks, html:JQuery) => {
         // If the window was reloaded, the JQuery is the Form
         let formHtml : HTMLFormElement | undefined;
         if(windowContent.classList.contains("window-app") && windowContent instanceof HTMLDivElement){
-            let potentialForm = windowContent.lastElementChild?.lastElementChild;
-            if(potentialForm instanceof HTMLFormElement){
-                formHtml = potentialForm;
-            }
+            formHtml = windowContent.querySelector("form");
         } else if(windowContent instanceof HTMLFormElement){
             formHtml = windowContent;
         }