Revert to a deliberate priority binding lookup fail

Just for the moment; just to see if I can get this to fail normally in CI.

Author: davep

src/textual/app.py

@@ -1742,9 +1742,10 @@ async def check_bindings(self, key: str, priority: bool = False) -> bool:
             bool: True if the key was handled by a binding, otherwise False
         """
 
-        for namespace, bindings in (
-            list(reversed(self._binding_chain)) if priority else self._binding_chain
-        ):
+        # for namespace, bindings in (
+        #     list(reversed(self._binding_chain)) if priority else self._binding_chain
+        # ):
+        for namespace, bindings in self._binding_chain:
             binding = bindings.keys.get(key)
             if binding is not None and binding.priority == priority:
                 await self.action(binding.action, default_namespace=namespace)