disable update of domain in demo mode

we removed the locked flag, so we have to add this check

src/cloudron.js

@@ -251,6 +251,8 @@ function prepareDashboardDomain(domain, auditSource, callback) {
 
     debug(`prepareDashboardDomain: ${domain}`);
 
+    if (settings.isDemo()) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     domains.get(domain, function (error, domainObject) {
         if (error) return callback(error);
 
@@ -308,6 +310,8 @@ function setDashboardAndMailDomain(domain, auditSource, callback) {
 
     debug(`setDashboardAndMailDomain: ${domain}`);
 
+    if (settings.isDemo()) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     setDashboardDomain(domain, auditSource, function (error) {
         if (error) return callback(error);
 

src/domains.js

@@ -253,6 +253,8 @@ function update(domain, data, auditSource, callback) {
 
     let { zoneName, provider, config, fallbackCertificate, tlsConfig } = data;
 
+    if (settings.isDemo() && (domain === settings.adminDomain())) return callback(new BoxError(BoxError.CONFLICT, 'Not allowed in demo mode'));
+
     domaindb.get(domain, function (error, domainObject) {
         if (error) return callback(error);