Handle realtime channel errors

[owenpearson]

Spec: RTL14
Transition channel state to FAILED upon receipt of an ERROR protocol message with a channel field matching the channel name. RealtimeChannel.error_reason should also be set to the error.

[sync-by-unito]

➤ Automation for Jira commented:

The link to the corresponding Jira issue is https://ably.atlassian.net/browse/SDK-3341