wizard: avoid a no-op

This removes a warning on a no-op being fired when the wizard changes a
state when the request for creation comes back as a success.
Instead don't update the form state if the wizard is going to be closed
anyway.

src/Components/CreateImageWizard/CreateImageWizard.js

@@ -567,8 +567,6 @@ const CreateImageWizard = () => {
                 title: 'Your image is being created',
               })
             );
-
-            setIsSaving(false);
           })
           .catch((err) => {
             let msg = err.response.statusText;