4ti2: Update to 1.6.10, fixes egrep issue, adds GCC 13 support

[mkoeppe]

📚 Description

Just released: https://github.com/4ti2/4ti2/releases/tag/Release_1_6_10,
with portability fixes, in particular for:

• Support GCC 13 (fedora-38) #35092

Resolves #30344

📝 Checklist

• The title is concise, informative, and self-explanatory.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[github-actions]

Documentation preview for this PR is ready! 🎉
Built with commit: 44a1878

[dimpase]

lgtm

[mkoeppe]

Thanks, Dima!