2311: Get individual preference opt-in status

Fetch entity preference subscription details for a single preference

Endpoint ID:	2311
Method:	GET
URL:	/preferences/entity/id/{entityID}/preference/{preferenceID} /preferences/entity/ext-key/{ext-key}/{ext-type}/preference/{preferenceID}
	entityID	Rubiq master ID that uniquely identifies the entity
	ext-key	External key that uniquely identifies the entity
	ext-type	Type of external key
	preferenceID	A GUID string identifier for the preference
Request body:	None
Response body:	Boolean value, where `true` indicates that the entity has opted in to this preference, and `false` indicates the entity has either opted in and subsequently opted out again, or has never opted in.
Status codes:	200	OK
	404	The entity or preference were not found. The following sub codes may be returned: `404.1` Entity not found `404.2` External entity reference not found `404.4` Preference not found