Bump phpoffice/phpspreadsheet from 1.29.4 to 1.29.7 in /src

Bumps [phpoffice/phpspreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) from 1.29.4 to 1.29.7.
- [Release notes](https://github.com/PHPOffice/PhpSpreadsheet/releases)
- [Changelog](https://github.com/PHPOffice/PhpSpreadsheet/blob/1.29.7/CHANGELOG.md)
- [Commits](PHPOffice/PhpSpreadsheet@1.29.4...1.29.7)

---
updated-dependencies:
- dependency-name: phpoffice/phpspreadsheet
  dependency-type: indirect
...

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