fix(landingpage): Do not show the Show Templates button on public share

[tintou]

📝 Summary

• Resolves: Hide the templates when looking at a document read-only #1709

The user is not going to do some edition at this point, do not allow them to list the templates.

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[mejo-]

Thanks for your contribution, much appreciated! I left a comment.

[mejo-]

Requested changes.

[github-actions]

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