Object Store with IRSA not working

I have applied the following configuration to my cluster in order to enable WAL archiving.
My Object storage is S3, CNPG is running in EKS, and I want to configure access via IRSA.

Cluster:
```
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
spec:
serviceAccountTemplate:
metadata:
annotations:
eks.amazonaws.com/role-arn: arn:aws:iam::
plugins:
- name: barman-cloud.cloudnative-pg.io
isWALArchiver: true
parameters:
barmanObjectName: objectstore
```

ObjectStore:
```
apiVersion: barmancloud.cnpg.io/v1
kind: ObjectStore
metadata:
name: objectstore
spec:
configuration:
data:
compression: bzip2
destinationPath: s3:///
wal:
compression: bzip2
maxParallel: 16
```

Policy attached to SA:
```
{
Action: [
"s3:PutObject",
"s3:GetObject",
"s3:ListBucket",
"s3:DeleteObject",
],
Effect: "Allow",
Resource: [
"arn:aws:s3:::",
"arn:aws:s3:::/*",
],
},
```

However, the WAL archiving is not working with the following error, complaining about missing Azure credentials even though my Object Storage is hosted by AWS.

```
{"level":"error","ts":"2025-08-13T17:06:02.383971021Z","logger":"wal-archive","msg":"Error while calling ArchiveWAL, failing","pluginName":"barman-cloud.cloudnative-pg.io","logging_pod":"metabase-database-3","error":"rpc error: code = Unknown desc = missing Azure credentials","stacktrace":"github.com/cloudnative-pg/machinery/pkg/log.(*logger).Error\n\tpkg/mod/github.com/cloudnative-pg/machinery@v0.3.0/pkg/log/log.go:125\ngithub.com/cloudnative-pg/cloudnative-pg/internal/cnpi/plugin/client.(*data).ArchiveWAL\n\tinternal/cnpi/plugin/client/wal.go:69\ngithub.com/cloudnative-pg/cloudnative-pg/pkg/management/postgres/archiver.archiveWALViaPlugins\n\tpkg/management/postgres/archiver/archiver.go:295\ngithub.com/cloudnative-pg/cloudnative-pg/pkg/management/postgres/archiver.internalRun\n\tpkg/management/postgres/archiver/archiver.go:156\ngithub.com/cloudnative-pg/cloudnative-pg/pkg/management/postgres/archiver.Run\n\tpkg/management/postgres/archiver/archiver.go:141\ngithub.com/cloudnative-pg/cloudnative-pg/internal/cmd/manager/walarchive.NewCmd.func1\n\tinternal/cmd/manager/walarchive/cmd.go:65\ngithub.com/spf13/cobra.(*Command).execute\n\tpkg/mod/github.com/spf13/cobra@v1.9.1/command.go:1015\ngithub.com/spf13/cobra.(*Command).ExecuteC\n\tpkg/mod/github.com/spf13/cobra@v1.9.1/command.go:1148\ngithub.com/spf13/cobra.(*Command).Execute\n\tpkg/mod/github.com/spf13/cobra@v1.9.1/command.go:1071\nmain.main\n\tcmd/manager/main.go:71\nruntime.main\n\t/opt/hostedtoolcache/go/1.24.5/x64/src/runtime/proc.go:283"}
```

Versions:
CNPG 1.26.1
Barman Cloud Plugin 0.5.0

Bắt đầu bằng cách lần theo đường dẫn lưu trữ WAL qua internal/cnpi/plugin/client/wal.go và pkg/management/postgres/archiver/archiver.go, sử dụng cấu hình CNPG 1.26.1 và Barman Cloud Plugin 0.5.0 được báo cáo làm ngữ cảnh tái hiện. Xác định lý do thiết lập AWS S3 này yêu cầu thông tin xác thực Azure, sau đó xác minh hành vi bằng một plugin test hoặc integration test phù hợp; hoàn thành khi việc lưu trữ WAL hoạt động thông qua IRSA mà không gặp lỗi thông tin xác thực Azure.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.