Add an emoji reaction to a LinkedIn message.
Full message URN (e.g. 'urn:li:msg_message:(urn:li:fsd_profile:ACoAAXXX,2-MTcw...)')
Emoji character to react with (e.g. '👍', '❤️', '😂')
Conversation URN for the thread to react in.
Reaction added
Credits consumed by this call (0 for free endpoints, cached results, or duplicates).
Seconds to wait before making another call of the same type. 0 means no wait needed.