Remove /v0/activities from scan APIs

[isegall-da]

Part of #4520

Pull Request Checklist

Cluster Testing

• If a cluster test is required, comment /cluster_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.
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• If a logical synchronizer upgrade test is required (from canton-3.5), comment /lsu_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.

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[OriolMunoz-da]

💣

[ray-roestenburg-da]

💥