Bug 1785094 - Stop applying --lwt-tab-loading-fill-inactive to the "connecting" state. r=Itiel

Differential Revision: https://phabricator.services.mozilla.com/D154802

browser/themes/shared/tabs.css

@@ -270,11 +270,6 @@
     100% { transform: translateX(100%); }
   }
 
-  #TabsToolbar[brighttext] .tab-throbber[busy]:not([selected=true])::before {
-    fill: var(--lwt-tab-loading-fill-inactive, #717171);
-    opacity: 1;
-  }
-
   :root[sessionrestored] .tab-throbber[progress]::before {
     fill: var(--tab-loading-fill);
     opacity: 1;