[CHA-2957] Java: sync generated client and wire structured logging

[mogita]

Ticket

https://linear.app/stream/issue/CHA-2957/logging

Summary

Regenerates the Java SDK against chat master and wires the CHA-2957 structured logging through the generated service clients. Two commits, reviewable separately:

1. chore: sync generated client to chat master API — pure regen against current chat master. Removes the 4 external-storage importer endpoints (/imports/v2/external-storage get/upsert/delete/validate) that [CHA-3889] / #14776 gated as private/operator-only and hid from the public OpenAPI spec (Ignore: true; still routed but behind the external_storage_import feature flag). Adds importBlockList. Adds an id path param to getModerationRule/deleteModerationRule. Refreshes assorted model fields. No behavior change: the generated Impls still use the existing StreamRequest constructor.
2. feat: wire structured logging through the generated service clients — regenerated with the updated Java template so the generated *Impl clients construct StreamRequest with the StreamHTTPClient. This lets the client-level SLF4J logger reach the request layer, so the CHA-2957 logging events fire on real API calls (they were framework-only before this).

Notes for review

• The importer-endpoint removals are the intended [CHA-3889] de-publication, not a customer-facing break: those endpoints were beta + operator-only and hidden from the public spec, and callers hit NotAllowed without the feature flag regardless.
• Does not auto-release: the Java SDK only releases via the release-* branch flow. Publish later via the manual Release workflow when ready.