Use the form sheet presentation style for the Payment UI.

ios/chrome/browser/ui/payments/payment_request_coordinator.mm

Index: ios/chrome/browser/ui/payments/payment_request_coordinator.mm
diff --git a/ios/chrome/browser/ui/payments/payment_request_coordinator.mm b/ios/chrome/browser/ui/payments/payment_request_coordinator.mm
index f29242285850881bed195c29d376f48e4d27d368..991e2ee7f172243b0fd09b3203d01ee9fde47999 100644
--- a/ios/chrome/browser/ui/payments/payment_request_coordinator.mm
+++ b/ios/chrome/browser/ui/payments/payment_request_coordinator.mm
@@ -171,6 +171,10 @@ class FullCardRequester
 
   _navigationController = [[UINavigationController alloc]
       initWithRootViewController:_viewController];
+  [_navigationController
+      setModalPresentationStyle:UIModalPresentationFormSheet];
+  [_navigationController
+      setModalTransitionStyle:UIModalTransitionStyleCoverVertical];
   [_navigationController setNavigationBarHidden:YES];
 
   [[self baseViewController] presentViewController:_navigationController