feat: add targetUserId to UserQueryFutureChannelBansRequestData

Add target_user_id parameter to allow filtering future channel bans
by target user, especially for client-side requests.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: totalimmersion

src/main/java/io/getstream/chat/java/models/User.java

@@ -1221,6 +1221,10 @@ public static class UserQueryFutureChannelBansRequestData {
     @JsonProperty("user_id")
     private String userId;
 
+    @Nullable
+    @JsonProperty("target_user_id")
+    private String targetUserId;
+
     @Nullable
     @JsonProperty("exclude_expired_bans")
     private Boolean excludeExpiredBans;