[AF] Remove iOS WebView PaymentsInterface reliance on VCN flag

Initially brought up in this comment and then discussed over chat where
the consensus was that removing the check is safe:
https://chromium-review.googlesource.com/c/chromium/src/+/7206766/2/components/autofill/core/browser/payments/virtual_card_enrollment_manager.cc#452

Bug: none
Change-Id: I5478f0e9900c1162757539d948109235fdf4d98c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7254644
Commit-Queue: Olivia Saul <osaul@google.com>
Reviewed-by: Carlos Acosta <cyacosta@google.com>
Reviewed-by: Tommy Martino <tmartino@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1558283}

ios/web_view/internal/autofill/ios_web_view_payments_autofill_client.mm

diff --git a/ios/web_view/internal/autofill/ios_web_view_payments_autofill_client.mm b/ios/web_view/internal/autofill/ios_web_view_payments_autofill_client.mm
index c996b5a..e84b91dc 100644
--- a/ios/web_view/internal/autofill/ios_web_view_payments_autofill_client.mm
+++ b/ios/web_view/internal/autofill/ios_web_view_payments_autofill_client.mm
@@ -215,16 +215,13 @@
 
 MultipleRequestPaymentsNetworkInterface*
 IOSWebViewPaymentsAutofillClient::GetMultipleRequestPaymentsNetworkInterface() {
-  if (GetPrefService()->GetBoolean(ios_web_view::kCWVAutofillVCNUsageEnabled)) {
-    if (!multiple_request_payments_network_interface_) {
-      multiple_request_payments_network_interface_ =
-          std::make_unique<payments::MultipleRequestPaymentsNetworkInterface>(
-              client_->GetURLLoaderFactory(), *client_->GetIdentityManager(),
-              web_state_->GetBrowserState()->IsOffTheRecord());
-    }
-    return multiple_request_payments_network_interface_.get();
+  if (!multiple_request_payments_network_interface_) {
+    multiple_request_payments_network_interface_ =
+        std::make_unique<payments::MultipleRequestPaymentsNetworkInterface>(
+            client_->GetURLLoaderFactory(), *client_->GetIdentityManager(),
+            web_state_->GetBrowserState()->IsOffTheRecord());
   }
-  return nullptr;
+  return multiple_request_payments_network_interface_.get();
 }
 
 void IOSWebViewPaymentsAutofillClient::ShowAutofillErrorDialog(