Allow unsubscribe from the conversation subscribe API

[iAmmar7]

Description

The PR will allow the user to unsubscribe from the conversation API.

Type of change

• [ ] Internal refactoring
• [ ] Bug fix (bugfix - non-breaking)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Code snippets

const { unsubscribe } = await client.conversation.subscribe(() => { ... })
unsubscribe();