Bump phpmailer/phpmailer from 6.8.1 to 6.9.1

Bumps [phpmailer/phpmailer](https://github.com/PHPMailer/PHPMailer) from 6.8.1 to 6.9.1.
- [Release notes](https://github.com/PHPMailer/PHPMailer/releases)
- [Changelog](https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md)
- [Commits](PHPMailer/PHPMailer@v6.8.1...v6.9.1)

---
updated-dependencies:
- dependency-name: phpmailer/phpmailer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Fixes #33350, PR #1943

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>