Pass empty scope to Twitch OAuth

[Mammonator]

Hello,

I am making an application that uses Twitch OAuth. The default scope in the implementation is user:read:email, which I do not need for this application. Not requiring email permissions will make applications such as this easier to trust, since an empty scope only returns public information.

Ideally, it should be possible to pass an empty string as a scope, but it seems like this is ignored in the gotrue fork:

func NewTwitchProvider(ext conf.OAuthProviderConfiguration, scopes string) (OAuthProvider, error) {
	if err := ext.Validate(); err != nil {
		return nil, err
	}

	apiHost := chooseHost(ext.URL, defaultTwitchAPIBase)
	authHost := chooseHost(ext.URL, defaultTwitchAuthBase)

	oauthScopes := []string{
		"user:read:email",
	}

	if scopes != "" {
		oauthScopes = append(oauthScopes, strings.Split(scopes, ",")...)
	}

Maybe it should be possible for the client to pass null, or an empty string to get an empty scope?