grpc api: Session close should also close corresponding listeners for proposal and updates

[danielksan81]

Motivation / Context

In the current implementation a session can be closed and the listeners are still open.

Expectation is that only if a session is open, listeners are valid and existent.

Maybe an alternative option is to add a flag to the method (true/false), which is targeting closing corresponding listeners if set to true. Default it will be false and preserve open listeners.

Description

Session close should also contain the following logic:

• Check for open channel proposal listeners for that session.
• Close found channel proposal listeners.
• Check for open channel update listeners.
• Close found channel update listeners.

Relates to