ci: drop the renovate rebase dispatch

[BryanFRD]

Renovate now runs as a CronJob in the cluster (FerrLabs/Infra#424), and FerrLabs/.github#339 removes renovate.yml and reusable-renovate-dispatch.yml. The "rebase now" dispatch has nothing left to trigger: a ticked checkbox is handled by the next in-cluster run (every 2 h).

Merge after FerrLabs/.github#339.

[ferrfleet]

Clean deletion, this is step 3 of the merge order in FerrLabs/.github#339.

Checked: nothing else in the repo references renovate-rebase.yml or reusable-renovate-dispatch.yml. renovate.json still extends github>FerrLabs/.github, which stays valid since default.json remains in the org repo for the CronJob to fetch. The pull_request: [edited] trigger was the only consumer of the reusable workflow here.

Ordering is safe either way: the uses: is pinned to SHA 539e9ac, so this workflow would still resolve even if .github#339 merged first. No reason to hold the merge on it beyond the in-cluster run being confirmed.

Nothing blocking.

[github-actions]

SonarQube — aucune nouvelle issue

_{Comparaison entre le projet bac à sable de cette PR et la branche par défaut : SonarQube Community n'analyse pas les PR, ce delta est calculé côté CI. Détail}