[WebAuthn] Unable to submit new requests after cancelling conditional…

… mediation via abortSignal

rdar://124727713
https://bugs.webkit.org/show_bug.cgi?id=271257

Reviewed by Charlie Wolfe.

In https://bugs.webkit.org/show_bug.cgi?id=257176, functionality was introduced to wait for a
previous request's cancel to complete before submitting a subsequent one. However, there's currently
a bug that does not set the cancel flag to false if there's no subsequent request.

This patch fixes that bug by setting m_isCancelling to false once the cancel completes regardless of
if there's a subsequent request.

* Source/WebCore/Modules/webauthn/AuthenticatorCoordinator.cpp:
(WebCore::AuthenticatorCoordinator::create):
(WebCore::AuthenticatorCoordinator::discoverFromExternalSource):

Canonical link: https://commits.webkit.org/276368@main

Source/WebCore/Modules/webauthn/AuthenticatorCoordinator.cpp

@@ -185,10 +185,9 @@ void AuthenticatorCoordinator::create(const Document& document, CredentialCreati
             weakThis->m_client->cancel([weakThis = WTFMove(weakThis)] () mutable {
                 if (!weakThis)
                     return;
-                if (auto queuedRequest = WTFMove(weakThis->m_queuedRequest)) {
-                    weakThis->m_isCancelling = false;
+                weakThis->m_isCancelling = false;
+                if (auto queuedRequest = WTFMove(weakThis->m_queuedRequest))
                     queuedRequest();
-                }
             });
         });
     }
@@ -289,10 +288,9 @@ void AuthenticatorCoordinator::discoverFromExternalSource(const Document& docume
             weakThis->m_client->cancel([weakThis = WTFMove(weakThis)] () mutable {
                 if (!weakThis)
                     return;
-                if (auto queuedRequest = WTFMove(weakThis->m_queuedRequest)) {
-                    weakThis->m_isCancelling = false;
+                weakThis->m_isCancelling = false;
+                if (auto queuedRequest = WTFMove(weakThis->m_queuedRequest))
                     queuedRequest();
-                }
             });
         });
     }