Bump tinymce/tinymce from 7.8.0 to 7.9.0 (#4817)

Bumps [tinymce/tinymce](https://github.com/tinymce/tinymce-dist) from 7.8.0 to 7.9.0.
- [Changelog](https://github.com/tinymce/tinymce-dist/blob/master/CHANGELOG.md)
- [Commits](tinymce/tinymce-dist@7.8.0...7.9.0)

---
updated-dependencies:
- dependency-name: tinymce/tinymce
  dependency-version: 7.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]