fcds: add listener integration test (#47189)

## Description

This PR added an integration test to validate the draining behavior for
FCDS.

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**Commit Message**: fcds: add listener integration test
**Risk Level:** Low
**Testing:** CI
**Docs Changes:** N/A
**Release Notes**: N/A

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Signed-off-by: Rohit Agrawal <rohit.agrawal@databricks.com>