chore(deps): update collabora/code docker tag to v26 (main)

[renovate]

This PR contains the following updates:

Package	Update	Change
collabora/code	major	25.04.10.3.1 → 26.04.1.4.1

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[EuklidAlexandria]

The 26 image does not bundle curl nor an alternative as wget or netcat anymore. The old healthcheck writing to the raw TCP socket via bash works. To fix the Collabora error message in #208, the HTTP header Connection: close can be added. The complete test command would be:

test: ["CMD", "bash", "-c", "exec 3<>/dev/tcp/127.0.0.1/9980 && echo -e 'GET /hosting/discovery HTTP/1.1\r\nHost: localhost:9980\r\nConnection: close\r\n\r\n' >&3 && head -n 1 <&3 | grep -q '200 OK'"]