AuthenticationRequest.canSaveCredentials

Determine whether this #WebKitAuthenticationRequest should allow the storage of credentials.

Determine whether the authentication method associated with this #WebKitAuthenticationRequest should allow the storage of credentials. This will return false if WebKit doesn't support credential storing, if private browsing is enabled, or if persistent credential storage has been disabled in #WebKitWebsiteDataManager, unless credentials saving has been explicitly enabled with [webkit.authentication_request.AuthenticationRequest.setCanSaveCredentials].