Fix handling of non-positive expiry times in punishment history

frontend/src/app/bans/history/history.component.ts

@@ -79,7 +79,7 @@ export class HistoryComponent implements OnInit, OnChanges {
   }
 
   public getExpiredTime(entry: PunishmentHistoryInner) {
-    if (entry.expiryTime === 0) {
+    if (entry.expiryTime <= 0) {
       return "Permanent " + this.getType(entry);
     }
     const date = new Date(entry.expiryTime);