Bugfix: migratelegacydata warn if no valid content dimension configuration

[mhsdesign]

@grebaldi stumbled upon this while migrating the Neos UI testing distribution. https://neos-project.slack.com/archives/C3MCBK6S2/p1688648280110549

in case you dindt migrate your dimensions first (eg the default repository doesnt have a dimension configuration) but you previously used dimensions in neos 8, then you will face this error:

Failed to find parent node for node with id "f676459d-ca77-44bc-aeea-44114814c279" and dimensions: {"language":"fr"}. The old CR can sometimes have orphaned nodes.

@grebaldi wrote

After running through, I export via ./flow cr:export. In the resulting file, I find only two events: ContentStreamWasCreated and RootNodeAggregateWithNodeWasCreated. Looks to me as if the legacy migration mistook every node of the test site for an orphaned node.

we debugged the NodeDataToEventsProcessor and after some time had the correct guess that we need to first configure the dimensions.

A few hours of debugging can save us 5 minutes of reading the documentation ^^ (well there is no documentation yet also ^^)

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[mhsdesign]

im not sure if this tipp is enough, or we should try to auto migrate the configuration?