fix: remove special styling from pinned tabs

Author: devvaannsh

src/styles/Extn-TabBar.less

@@ -276,14 +276,6 @@
     background-color: rgba(255, 255, 255, 0.1);
 }
 
-.tab.pinned {
-    background-color: rgba(0, 100, 200, 0.05);
-}
-
-.dark .tab.pinned {
-    background-color: rgba(100, 150, 255, 0.1);
-}
-
 .tab.placeholder .tab-name {
     font-style: italic;
     color: #999;