Support graceful shutdown TiCDC node

[overvenus]

Feature Request

Is your feature request related to a problem? Please describe:

TiCDC replication latency is increased when we shutdown a TiCDC node.

See pingcap/tiflow#4757

Describe the feature you'd like:

Support graceful shutdown TiCDC node to minimize the impact to replication latency.

Describe alternatives you've considered:

N/A

Teachability, Documentation, Adoption, Migration Strategy:

N/A