allow clearing FIFO config as fallback (#14338)

FIFO is already removed, for users who upgrade are allowed to clear their configs.

cmd/admin-bucket-handlers.go

@@ -71,6 +71,11 @@ func (a adminAPIHandlers) PutBucketQuotaConfigHandler(w http.ResponseWriter, r *
 		return
 	}
 
+	if quotaConfig.Type == "fifo" {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidRequest), r.URL)
+		return
+	}
+
 	if err = globalBucketMetadataSys.Update(ctx, bucket, bucketQuotaConfigFile, data); err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return