Need a way to propagate tenant id from side effects in Marten to Wolverine messaging

[jeremydmiller]

Tenant id for the outgoing message needs to be taken from the EventSlice correctly. Getting lost for TC

[jeremydmiller]

Done in 7.0, but we can't cherry pick that commit, so leaving this open to add the same work to the master / 8.0 branch. Good times.

[jeremydmiller]

Done in Marten 8 / Wolverine 4 as well. Not committed yet, but closing this