Changes

feat(tikv/migration): migrate CI artifacts from fileserver to OCI registry (#4272)

Migrates `tikv/migration` integration CI jobs from
`fileserver.pingcap.net` to OCI artifacts in
`hub-zot.pingcap.net/mirrors/hub`.

## Changes
- update `pull_integration_test.groovy` and
`pull_integration_kafka_test.groovy` to prepare integration binaries via
OCI
- preserve `make prepare_test_binaries` semantics by downloading
required artifacts into `cdc/scripts/bin` (`tidb-server`, `tikv-server`,
`pd-server`, `pd-ctl`, `etcdctl`, `go-ycsb`)
- set `OCI_ARTIFACT_HOST` to `hub-zot.pingcap.net/mirrors/hub` in
integration pipelines
- add `utils` sidecar (`ghcr.io/pingcap-qe/cd/utils/release`) in
integration pod templates for OCI tooling support
- keep integration presubmit triggers in
`prow-jobs/tikv/migration/latest-presubmits.yaml` with shared YAML
anchors

## Follow-up split out
- `pull_unit_test` removal is tracked separately in #4300 and
implemented in #4301

Fixes #4215

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wuhuizuo <2574558+wuhuizuo@users.noreply.github.com>
Co-authored-by: wuhuizuo <wuhuizuo@126.com>
Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>
 (commit: 9e255f9)