Tombstone processing needs to track tenant id

[jeremydmiller]

Here's the culprit:

    private async Task executeTombstoneBlock(UpdateBatch batch, CancellationToken cancellationToken)
    {
        await using var session = (DocumentSessionBase)_store.LightweightSession();
        await session.ExecuteBatchAsync(batch, cancellationToken).ConfigureAwait(false);
    }

That method needs to be tenant aware

[jeremydmiller]

This was fixed, lost sight of when exactly