(js) Fix saving draft outside Mail module

Fixes #4071

UI/WebServerResources/js/Mailer/Message.service.js

@@ -129,6 +129,9 @@
     if (options && options.asDraft && this.draftId) {
       id = buildPath() + '/' + this.draftId; // add draft ID
     }
+    if (options && options.withResourcePath) {
+      id = Message.$$resource.path(id); // return absolute URL
+    }
 
     return id;
   };

UI/WebServerResources/js/Mailer/MessageEditorController.js

@@ -33,7 +33,7 @@
     vm.sendState = false;
     vm.toggleFullscreen = toggleFullscreen;
     vm.uploader = new FileUploader({
-      url: stateMessage.$absolutePath({asDraft: true}) + '/save',
+      url: stateMessage.$absolutePath({asDraft: true, withResourcePath: true}) + '/save',
       autoUpload: true,
       alias: 'attachments',
       removeAfterUpload: false,