Attach (recommended) or Link to PDF file here:
[PDFBOX-5275-p5.pdf](https://github.com/mozilla/pdf.js/files/7109095/PDFBOX-5275-p5.pdf)

Configuration:
- Web browser and its version: FF 91.0.2
- Operating system and its version: Windows 10.0.19043.1165
- PDF.js version: latest (tried with https://mozilla.github.io/pdf.js/web/viewer.html )

Steps to reproduce the problem:
1. open the file
2.

What is the expected behavior? Displays a plant

What went wrong? Displays blank page

See also
https://issues.apache.org/jira/browse/PDFBOX-5275
which had the same problem, the cause was bad handling of an empty OCGs entry

![grafik](https://user-images.githubusercontent.com/6665575/132079956-c48921bf-6dbb-4e89-886e-4301d955ee35.png)


/* Copyright 2020 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { objectFromMap, warn } from "../shared/util.js";
class OptionalContentGroup {
  constructor(name, intent) {
    this.visible = true;
    this.name = name;
    this.intent = intent;
  }
}
class OptionalContentConfig {