Cleanup webview only if a new one was created by the ADAuthenticationViewController.
Cleanup webview only if a new one was created by the ADAuthenticationViewController.

AzureAD/azure-activedirectory-library-for-objc,AzureAD/azure-activedirectory-library-for-objc,AzureAD/azure-activedirectory-library-for-objc,AzureAD/azure-activedirectory-library-for-objc,AzureAD/azure-activedirectory-library-for-objc