PackageToJS: Fix missing await for page.exposeFunction

It caused concurrent calls to `exposeFunction` and resulted losing
the function bindings after the playwright upgrade.

Author: kateinoigakukun

Plugins/PackageToJS/Templates/bin/test.js

@@ -116,7 +116,7 @@ Hint: This typically means that a continuation leak occurred.
                         for (const [name, fn] of Object.entries(functions)) {
                             // Bind the page context to each function if needed
                             // The function can optionally use the page from its closure
-                            page.exposeFunction(name, fn);
+                            await page.exposeFunction(name, fn);
                         }
                     };
                 }

Plugins/PackageToJS/Templates/test.js

@@ -108,10 +108,12 @@ Please run the following command to install it:
     page.on("console", (message) => {
         console.log(message.text());
     });
-    
+
+    let resolveExit = undefined;
     const onExit = new Promise((resolve) => {
-        page.exposeFunction("exitTest", resolve);
+        resolveExit = resolve;
     });
+    await page.exposeFunction("exitTest", resolveExit);
     await page.goto(`http://localhost:${address.port}/test.browser.html`);
     const exitCode = await onExit;
     await browser.close();