Revert first list width change.

Related https://github.com/wekan/wekan/pull/4993

Thanks to xet7 !

client/components/lists/list.css

@@ -16,6 +16,7 @@
   /* overflow: auto; - List width and height resizeable */
 }
 .list:first-child {
+  min-width: 20px;
   margin-left: 5px;
   border-left: none;
 }