Quite probably never. The current implementation is a "type 2" add-on which can only go into Cloud if Atlassian decide to support it. They're currently not accepting any new add-ons of that type.
I don't know if a Connect version may in the works though
It would be better to ask the add-on vendor directly if they have any plans to move their add-on to Cloud. By asking them the question you might encourage them to do so.
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