[oform] Fix weight when add a field group

oform/Document.js

@@ -372,7 +372,7 @@
 		for (let index = 0, count = this.FieldGroups.length; index < count; ++index)
 		{
 			let curWeight = this.FieldGroups[index].getWeight();
-			if (max > curWeight)
+			if (max < curWeight)
 				max = curWeight;
 		}
 		

oform/OForm.js

@@ -241,6 +241,7 @@
 		
 		// Нельзя, чтобы групп не было вообще
 		let defaultGroup = new AscOForm.CFieldGroup();
+		defaultGroup.setWeight(this.Format.getMaxWeight() + 1);
 		this.Format.addFieldGroup(defaultGroup);
 		defaultGroup.addUser(this.Format.getDefaultUser());
 	};