Changed log level for retryable error Scenarios

[anandmukul93]

1- xDS DeltaDiscoveryRequest context cancelled set to INFO on stream cancelled as it is retrieable
2- subscription failed logging on ACL change is set to INFO as is also retriable

Description

For an enterprise ask as referred in an internal JIRA ticket.

Testing & Reproduction steps

Testing reproduction done -
1 - created a new build with consul changes in local and container image with binary.
2 - used the new image to start consul server with dev-binary inside a kind cluster
3 - start a service and shut down a service to see the above logs.
4 - Since only ACL change occurred and context cancelled are being handled currently with the corresponding understanding that they are retriable, others are cases will still be in error level .
5- As you can see in the last three lines - to get INFO level lines. run a consul server and try to shut down a service
6 - check that these log lines appear as INFO level

2025-02-07T13:33:08.027Z [INFO] agent.envoy: Error receiving new DeltaDiscoveryRequest; closing request channel: error="rpc error: code = Canceled desc = context canceled"

2025-02-07T13:33:14.026Z [INFO] agent.proxycfg.server-data-sources: subscribe call failed: err="subscription closed by server, ACL change occurred" failure_count=1 key=mesh topic=MeshConfig

2025-02-07T13:33:14.026Z [INFO] agent.proxycfg.server-data-sources: subscribe call failed: err="subscription closed by server, ACL change occurred" failure_count=1 topic=JWTProvider wildcard_subject=true

Links

Related past PR - #20876

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

[sreeram77]

LGTM!