Attach (recommended) or Link to PDF file here:
[test planning.pdf](https://github.com/mozilla/pdf.js/files/7305078/test.planning.pdf)

Configuration:
- Web browser and its version: Firefox 93
- Operating system and its version: Windows 10 21H2
- PDF.js version: The integrated version
- Is a browser extension: no

Steps to reproduce the problem:
1. In the example, all shape and the "Line" cell of the first cell have a comment
2. Mouse over a "Line" cell or a shape, nothing appear except on mouse over their border
3. It is too difficult to use
4. There is also a vertical orientation issue reported in bug #7631

What is the expected behavior? (add screenshot)
Comments are shown on mouse hover or mouse click inside a cell or a shape

What went wrong? (add screenshot)
Comments are not shown when mouse hover or clicking inside a cell or a shape, only on their border

![image](https://user-images.githubusercontent.com/7791600/136419088-e083e2a3-d376-4d8c-9e0b-ce9dd5b83923.png)



return wrapper;
  }
  /**
   * Format the contents of the popup by adding newlines where necessary.
   *
   * @private
   * @param {Object<string, string>} contentsObj
   * @memberof PopupElement
   * @returns {HTMLParagraphElement}
   */
  _formatContents({ str, dir }) {
    const p = document.createElement("p");
    p.dir = dir;
    const lines = str.split(/(?:\r\n?|\n)/);
    for (let i = 0, ii = lines.length; i < ii; ++i) {
      const line = lines[i];
      p.appendChild(document.createTextNode(line));
      if (i < ii - 1) {
        p.appendChild(document.createElement("br"));
      }
    }
    return p;
  }
  /**
   * Toggle the visibility of the popup.
   *
   * @private
   * @memberof PopupElement
   */
  _toggle() {