ClientDataSetId is not produced in an event

[Kubuxu]

ClientDataSetId is not emitted. While it is not that useful from an indexing standpoint, there are use cases that require it.
It came up while we were trying to reuse datasets we created, without keeping the state outside the indexer.

I could be convinced that this doesn't need to be emitted as well.

[BigLep]

@Kubuxu : I'm bumping this to later in 2026Q4, but please share if you think it needs to be done sooner.

[rjan90]

With the bump to 2026Q4, I´m also changing the Milestone here to MX.