Fix RCTDevLoadingView banner window sizing and interaction (#54702)

Summary:
Pull Request resolved: #54702

Changelog:
[iOS][Fixed] - Make rest of app responsive whilst dev loading banner present

The dev loading banner window was previously full-screen height, making the entire screen unresponsive to touches even though only a small banner was visible.

The window frame is now calculated after Auto Layout completes, ensuring it matches the actual content height (label + padding + safe area). This allows the rest of the screen below the banner to remain interactive.

The banner now only blocks interactions within its actual bounds

Reviewed By: vzaidman

Differential Revision: D87922708

fbshipit-source-id: d46d05915b5d91e269f1a53bca2a8bbdffb3267a

Author: emily8rown

packages/react-native/React/CoreModules/RCTDevLoadingView.mm

@@ -220,6 +220,9 @@ - (void)showMessage:(NSString *)message
     }
 
     [NSLayoutConstraint activateConstraints:constraints];
+
+    [self->_window layoutIfNeeded];
+    self->_window.frame = CGRectMake(0, 0, mainWindow.frame.size.width, self->_container.frame.size.height);
   });
 }