fix: Update gettext to 0.26 by building from source

[juliusknorr]

We had some translation strings in the whiteboard app that are not properly extracted within typescript jsx templates:

https://github.com/nextcloud/whiteboard/blob/d3eec9a25e920efabaf10fd33280954be97aaf35/src/components/CreatorMenuItem.tsx#L58C9-L60C76

Testing locally with 0.26 does properly gather those strings.

[nickvergessen]

Any specific problem that can be linked?

[juliusknorr]

No issues but mentioned code reference in the first post now

[nickvergessen]

While building worked, executing failed.

Digest: sha256:ad77b999886ea5614f901262129201a99c657b29a70e11ba0385cdd7b15d940c
Status: Downloaded newer image for ghcr.io/nextcloud/continuous-integration-translations-app:latest
+ php -v
PHP 8.3.6 (cli) (built: Jan  7 2026 08:40:32) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.3.6, Copyright (c) Zend Technologies
    with Zend OPcache v8.3.6, Copyright (c), by Zend Technologies
+ tx -v
TX Client, version=1.6.17
+ xgettext -V
xgettext: error while loading shared libraries: libgettextsrc-0.26.so: cannot open shared object file: No such file or directory

CAn you have a look @juliusknorr