chore(deps): bump @tiptap/extension-placeholder

Bumps [@tiptap/extension-placeholder](https://github.com/ueberdosis/tiptap/tree/HEAD/packages/extension-placeholder) from 2.10.3 to 2.10.4.
- [Release notes](https://github.com/ueberdosis/tiptap/releases)
- [Changelog](https://github.com/ueberdosis/tiptap/blob/@tiptap/[email protected]/packages/extension-placeholder/CHANGELOG.md)
- [Commits](https://github.com/ueberdosis/tiptap/commits/@tiptap/[email protected]/packages/extension-placeholder)

---
updated-dependencies:
- dependency-name: "@tiptap/extension-placeholder"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>