Inject page in admin panel via Shopify.API.pushState

Summary `Shopify.API.pushState` call the method `handleRoutePushEvent`, allows you to change routes to open pages from admin panel:

handleRoutePushEvent({pathname: e, search: t, state: a, hash: o}) {
                const {adminPath: n, history: i} = this.props // `adminPath` = `/admin`
                  , s = "".concat(n).concat(e);
                // *** //
}