fix(core): update metadata before window-created listeners, closes #5191

Tauri fires event listeners in reverse order, so our own tauri://window-created listener is the last to execute. This commit changes the listen JS code to keep our own listener as the last one in the array, so the metadata is updated before user code is executed.

.changes/fix-metadata-update.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Fixes access to the `WebviewWindow.getByLabel` function in a `tauri://window-created` event listener.

core/tauri/src/event.rs

@@ -327,17 +327,26 @@ pub fn listen_js(
   handler: String,
 ) -> String {
   format!(
-    "if (window['{listeners}'] === void 0) {{
-      Object.defineProperty(window, '{listeners}', {{ value: Object.create(null) }});
-    }}
-    if (window['{listeners}'][{event}] === void 0) {{
-      Object.defineProperty(window['{listeners}'], {event}, {{ value: [] }});
-    }}
-    window['{listeners}'][{event}].push({{
-      id: {event_id},
-      windowLabel: {window_label},
-      handler: {handler}
-    }});
+    "
+    (function () {{
+      if (window['{listeners}'] === void 0) {{
+        Object.defineProperty(window, '{listeners}', {{ value: Object.create(null) }});
+      }}
+      if (window['{listeners}'][{event}] === void 0) {{
+        Object.defineProperty(window['{listeners}'], {event}, {{ value: [] }});
+      }}
+      const eventListeners = window['{listeners}'][{event}]
+      const listener = {{
+        id: {event_id},
+        windowLabel: {window_label},
+        handler: {handler}
+      }};
+      if ({event} == 'tauri://window-created') {{
+        eventListeners.splice(eventListeners.length - 1, 0, listener)
+      }} else {{
+        eventListeners.push(listener);
+      }}
+    }})()
   ",
     listeners = listeners_object_name,
     event = event,