Changes

ci(prow): migrate tidb-binlog integration test to GCP (#4520)

## Background

This PR migrates the legacy
[binlog_ghpr_integration](https://ci2.pingcap.net/view/ghpr_binlog/job/binlog_ghpr_integration/)
Jenkins job into a GCP-compatible Prow Kubernetes presubmit for
`pingcap/tidb-binlog`.

Issue Number: ref https://github.com/PingCAP-QE/ci/issues/3342

## What Changed
The new `pull-integration-test` job now can be running on GCP as a
native prow job.
The new `pull-integration-test` job is intentionally scoped to the
maintained TiDB Binlog compatible lines only:
- `release-8.1`
- `release-7.5`
- `release-7.1` 

This pr keep the job non-gating as a staged rollout, the follow-up step
is to flip them to required after we gain enough confidence from the new
GCP lane.

## Implementation details

- rename the old WIP job to the formal `pull-integration-test`
- use public Kafka / Zookeeper images instead of `hub.pingcap.net`
- add a dedicated `scripts/pingcap/tidb-binlog/pull_integration_test.sh`
entry script
- download TiDB / TiKV / PD artifacts from OCI
- download `sync_diff_inspector` from OCI and remove the dependency on
`fileserver.pingcap.net`
- fail fast for unsupported base refs so the job stays focused on the
legacy-compatible release lines

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Signed-off-by: lyb <yebin.li@pingcap.com>
 (commit: 300b7fa)