Support configurable health check port for klusterlet agents in KlusterletSpec

[shivansh-source]

Background
Currently, the health check port for klusterlet agents (livenessProbe/readinessProbe) is hardcoded to 8443 in the OCM deployment manifests. This creates problems when using hostNetwork: true and the default port is already in use by another process on the node—leading to pod startup failures.

See related issue: ocm/1032

Ask
Extend the KlusterletSpec API to support configuration of the health check probe port for klusterlet-related agent controllers.

Proposal
Introduce a new optional AgentConfiguration field in KlusterletSpec

• Mirrors the existing approach used for webhook configuration in ClusterManager API (see DefaultWebhookConfiguration with BindConfiguration)
• Makes the klusterlet agent's health check port user-configurable via the Klusterlet CRD
• Avoids node port conflicts when using hostNetwork: true
• Increases OCM's flexibility for various deployment scenarios
• Brings API consistency across OCM component

Related OCM issue: ocm/1032
Similar pattern in ClusterManager: api/L424

[shivansh-source]

/cc @mikeshng issue made for ocm health check port issue fix
i will work on this
/assign