Bump pypdf from 6.0.0 to 6.6.0 in /pdf-processing

Bumps [pypdf](https://github.com/py-pdf/pypdf) from 6.0.0 to 6.6.0.
- [Release notes](https://github.com/py-pdf/pypdf/releases)
- [Changelog](https://github.com/py-pdf/pypdf/blob/main/CHANGELOG.md)
- [Commits](py-pdf/pypdf@6.0.0...6.6.0)

---
updated-dependencies:
- dependency-name: pypdf
  dependency-version: 6.6.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pdf-processing/requirements.txt

@@ -1,5 +1,5 @@
 # PDF Processing Dependencies
-pypdf==6.0.0
+pypdf==6.6.0
 pymupdf==1.24.0
 pdf2image==1.17.0
 pytesseract==0.3.13