community/ocrmypdf: upgrade to 16.4.1

https://raw.githubusercontent.com/ocrmypdf/OCRmyPDF/v16.4.1/docs/release_notes.rst

Newer version has 1 warning but otherwise passes tests.

<frozen importlib._bootstrap>:530                                         
  <frozen importlib._bootstrap>:530: DeprecationWarning: the load_module()
method is deprecated and slated for removal in Python 3.12; use exec_module() instead

cc @kdaudt re: !64743 (comment 416492)