plugin.Open audit-1 fails on v8.5.6: plugin was built with a different version of package internal/godebugs

## Bug Report

### 1. Minimal reproduce step

We hit a startup failure in a staging TiDB Cloud Azure environment when bringing up a `v8.5.6` `tidb-server` with audit plugin enabled.

The `tidb-server` process exits during startup while loading the plugin manifest.

### 2. What did you expect to see?

`tidb-server` should start successfully and load the configured plugin, or at least report a clearer compatibility error if cross-version plugin loading is unsupported.

### 3. What did you see instead?

`tidb-server` exits with:

```log
[FATAL] [terror.go:309] ["unexpected error"] [error="plugin.Open(\"/plugins/audit-1\"): plugin was built with a different version of package internal/godebugs"]
```

Relevant startup log excerpt:

```log
[INFO] [printer.go:52] ["Welcome to TiDB."] ["Release Version"=v8.5.6] [Edition=Enterprise] ["Git Commit Hash"=a5df4940be0ca5b7c324d182e67ce658fdad4474] ["UTC Build Time"="2026-03-24 10:45:26"] [GoVersion=go1.25.5]
[INFO] [plugin.go:377] ["start load plugin manifest"] [plugin=audit-1] [name=audit] [version=1]
[FATAL] [terror.go:309] ["unexpected error"] [error="plugin.Open(\"/plugins/audit-1\"): plugin was built with a different version of package internal/godebugs"] [stack="github.com/pingcap/tidb/pkg/parser/terror.MustNil\n\t/workspace/source/tidb/pkg/parser/terror/terror.go:309\nmain.createStoreDDLOwnerMgrAndDomain\n\t/workspace/source/tidb/cmd/tidb-server/main.go:417\nmain.main\n\t/workspace/source/tidb/cmd/tidb-server/main.go:320"]
```

### 4. What version of TiDB are you using (`tidb-server -V` or running `/tidb-server -V` on TiDB pod)?

`v8.5.6`

From startup log:
- Release Version: `v8.5.6`
- Edition: `Enterprise`
- Git Commit Hash: `a5df4940be0ca5b7c324d182e67ce658fdad4474`
- Build Time: `2026-03-24 10:45:26 UTC`
- GoVersion: `go1.25.5`

### 5. Environment

- Deployment: staging
- Platform: TiDB Cloud Azure
- Plugin enabled: `audit-1`
- `plugin_dir`: `/plugins`
- `plugin_load`: `audit-1`

### 6. Additional background

There is a mixed deployment setup behind this environment:
- the cluster version is `v8.5.5`
- operator v2 is used to support grouped deployment
- on the underlying layer, one additional `v8.5.6` `tidb-server` instance is deployed to achieve mixed deployment

This mixed deployment pattern had been working before, so we are not sure whether a recent packaging or build change introduced the issue.

### 7. Question

Could you help confirm:
- whether plugin binaries are expected to be compatible in this mixed deployment scenario,
- whether the `audit-1` plugin artifact was built with a different Go toolchain / `internal/godebugs` version than the `v8.5.6` tidb-server binary,
- and whether this is a packaging / release pipeline issue for the plugin artifact?