Center 2-columns layout without side effect (mastodon#10915)

Author: Hanage999

app/javascript/styles/mastodon/components.scss

@@ -1794,7 +1794,6 @@ a.account__display-name {
     height: 100%;
 
     &__pane {
-      flex: 1 1 auto;
       height: 100%;
       overflow: hidden;
       pointer-events: none;