[DevTools] Upon active timeline recording, label cursor should behave as a default cursor.

Source/devtools/front_end/inspector.css

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Anthony Ricaud <rik@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 29 matching lines @@
 }
 
 label {
     cursor: pointer;
 }
 
 label:hover input {
     box-shadow: 0 0 3px highlight;
 }
 
+label.dimmed {
+    opacity: 0.6;
+    cursor: default;
+}
+
 fieldset[disabled] label:hover input {
     box-shadow: none;
 }
 
 .fill {
     position: absolute;
     top: 0;
     left: 0;
     right: 0;
     bottom: 0;
@@ skipping 2861 matching lines @@
 }
 
 select.drop-down-menu {
     border: none;
     -webkit-appearance: none;
 }
 
 .viewport-control-gap-element {
     color: transparent;
 }