[Replication] Structure values are not replicated correctly when Seq.App.Replication is used with Seq 4

[nblumhardt]

Version 4 passes log data through as IReadOnlyDictionary<string, object>, not IDictionary<string, object>, which causes structure values to be replicated as strings.

The fix should be backwards-compatible, as v3's dictionaries will also support this interface.

[nblumhardt]

Published in version 2.0.66