editors/libreoffice: update to 7.2.6 release (+)

While HEAD was already pushed with latest, 7.3 branch of LibreOffice suite,
we're announcing LibreOffice 7.2.6, with 50+ bugfixes, to the quarterly users.

Read more: https://blog.documentfoundation.org/blog/2022/03/10/announcement-of-libreoffice-7-2-6-community/

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