Check we're not misusing `JSONValue(ablyCocoaData:)`

[lawrence-forooghian]

see e.g.

ably-chat-swift/Sources/AblyChat/AblyCocoaExtensions/InternalAblyCocoaTypes.swift

Lines 456 to 468 in 6be8bc6

	internal extension PresenceMessage {
	init(ablyCocoaPresenceMessage: ARTPresenceMessage) {
	clientId = ablyCocoaPresenceMessage.clientId
	timestamp = ablyCocoaPresenceMessage.timestamp
	action = ablyCocoaPresenceMessage.action
	if let ablyCocoaData = ablyCocoaPresenceMessage.data {
	data = JSONValue(ablyCocoaData: ablyCocoaData).objectValue
	}
	if let ablyCocoaExtras = ablyCocoaPresenceMessage.extras {
	extras = JSONValue.objectFromAblyCocoaExtras(ablyCocoaExtras)
	}
	}
	}

— what if the ably-cocoa message contains something else (e.g. Data, or something else that came over the wire that it couldn't decode, as represented by encoding?); we don't want to crash

┆Issue is synchronized with this Jira Task by Unito