Bug 1956952 - Add a probe for when CPM is enabled in sidebar customization panel. r=rsafaeian,sidebar-reviewers,kcochrane

Differential Revision: https://phabricator.services.mozilla.com/D243389

browser/components/sidebar/sidebar-customize.mjs

@@ -153,6 +153,11 @@ export class SidebarCustomize extends SidebarPage {
           checked: e.target.checked,
         });
         break;
+      case "viewCPMSidebar":
+        Glean.contextualManager.sidebarCustomizeEnabled.record({
+          checked: e.target.checked,
+        });
+        break;
     }
   }