Implement no-connection-serial - ( remove all references to connection serial )

[sacOO7]

• Remove all references to connection serial
• Update tests for the same

┆Issue is synchronized with this Jira Task by Unito

[sync-by-unito]

➤ Automation for Jira commented:

The link to the corresponding Jira issue is https://ably.atlassian.net/browse/SDK-3958