[Feature Request] Handle certificate hot reload for Flight server

[rishabhmaurya]

Is your feature request related to a problem? Please describe

FlightServer bootstrap logic introduced in #16962 doesn't handle hot reload of Ssl certificates which needs to be handled.

Describe the solution you'd like

Fix it by introducing a new event for hot reload requested via security plugin and listeners to use the latest certificate.

Related component

Search:Performance

Describe alternatives you've considered

No response

Additional context

No response

[sandeshkr419]

[Search Triage] @rishabhmaurya Are you continuing on this?

[rishabhmaurya]

As FlightTransport is initialized the way regular transport is initialized, certificate management is directly handled by security plugin now. More details on TLS and security integration is covered as part of doc - https://github.com/opensearch-project/OpenSearch/blob/main/plugins/arrow-flight-rpc/docs/security-integration.md
#18424 resolves it.