Changed width of signature avatar from auto to 16px (#12961)

Signed-off-by: Victor Roest <[email protected]>

Co-authored-by: Antoine GIRARD <[email protected]>

Author: Victor

web_src/less/_repository.less

@@ -1481,7 +1481,7 @@
     .ui.signature.avatar {
       height: 16px;
       margin-bottom: 0;
-      width: auto;
+      width: 16px;
     }
 
     .detail.icon {