ci(fix): update outdated minio client image in integration tests

[NohaIhab]

Summary

This PR fixes the failing MinIO integration checks by updating the client image used inside the temporary kubectl run pods.

The failing tests were creating a one-off MinIO client pod with an outdated image reference. In practice, that image failed to pull in CI, so the integration checks never reached the actual MinIO connectivity assertion. The test was failing before it validated the charm behavior itself.

Logs from the outdated image pull:

  Warning  Failed     43s (x3 over 84s)  kubelet            spec.containers{mc-debug-events}: Failed to pull image "minio/mc": failed to pull and unpack image "docker.io/minio/mc:latest": failed to resolve reference "docker.io/minio/mc:latest": pull access denied, repository does not exist or may require authorization: server message: insufficient_scope: authorization failed

Changes

• Updated the MinIO client image from the stale image reference to the supported registry:
  • quay.io/minio/mc
• Added a shared image constant in both integration test files:
  • MINIO_CLIENT_IMAGE = "quay.io/minio/mc"

Additional changes

• Also included a guaranteed cleanup for the pod: Add a run_probe_pod() helper that runs the one-off kubectl run pod and always deletes it in a finally block. This replaces the unreliable --rm flag, which only cleans up on a clean attached exit and leaves pods behind on the failure paths that matter here, this was previously causing name collisions on retries and between adjacent tests.

[ckfbot]

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Successfully created backport PR for track/1.10:

• ci(fix): update outdated minio client image in integration tests (backport #309) #310