stats/opentelemetry: Write e2e tests for tracing more than single message sent and received

[purnesh42H]

In all of the e2e tests, we only have single message being sent/received, which means that the logic on the sequence numbers incremented is untested. Write a separate test for streaming RPC where multiple messages are being sent and received and validate the traces accordingly

[vinothkumarr227]

@purnesh42H Please assign the issue to me.