Iris - check hit in FNetBitStreamWriter::InitBytes if object has only COND_InitialOnly replicated properties

InitOnly FReplicationStateDescriptors will have a value of 0 for ChangeMaskBitCount, so if an object only has COND_InitialOnly properties, its FReplicationProtocol will also have a ChangeMaskBitCount of 0.
This causes the check to fail in FNetBitStreamWriter::InitByte, as it expects the ByteCount to be at least 4.

Create a replicated subobject where all of its replicated properties use the COND_InitialOnly replication condition, and add this subobject to an actor.
When the replication system copies the dirty state data for this object, the following check will be hit in FNetBitStreamWriter::InitBytes: "Buffer capacity needs to be a multiple of 4 and at least 4."