ITS: fix clusterSize propagation

[f3sch]

After recent refactoring, this started to push to the end of the vector, which was preallocated.
@ddobrigk this should fix the cluster size in ao2d.

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[ddobrigk]

Super thanks for the very very fast debugging @f3sch !

[shahor02]

@f3sch @ddobrigk is this related to https://its.cern.ch/jira/browse/O2-5947?focusedId=6873358&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-6873358 ?

[ddobrigk]

@f3sch @ddobrigk is this related to https://its.cern.ch/jira/browse/O2-5947?focusedId=6873358&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-6873358 ?

Yes, exactly, I think this is it from private discussions - @f3sch can you confirm please?

[f3sch]

yes

[fprino]

Look good to me. Thanks for the fix!