PLT-5900 Removed automatic configuration of SiteURL (#5952)

* Revert "PLT-5765 Passed SiteURL to SendNotifications (#5705)"

This reverts commit a8e68bd890.

* Removed automatic configuration of SiteURL

* Reverted unintentional config changes

* Updated help text

* Added link to docs in Site URL warning

* Fixed merge conflict

webapp/stores/error_store.jsx

@@ -62,11 +62,11 @@ class ErrorStoreClass extends EventEmitter {
         BrowserStore.setGlobalItem('last_error_conn', count);
     }
 
-    clearLastError() {
+    clearLastError(force) {
         var lastError = this.getLastError();
 
         // preview message can only be cleared by clearNotificationError
-        if (lastError && lastError.notification) {
+        if (!force && lastError && lastError.notification) {
             return;
         }