Kill legacy setting_set on is_public

[tituspijean]

Stuck at level 4 due setting is_public setting.

https://ci-apps.yunohost.org/ci/job/9825

PR Status

• [x] Code finished and ready to be reviewed/tested
• [ ] The fix/enhancement were manually tested (if applicable)

Automatic tests

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[tituspijean]

!testme

[yunohost-bot]

:v: