fix: search within context node paths

[haase-fabian]

I noticed that the search does not do a query inside the given context node. But rather within all Siblings of that Node.

$subgraph->findAncestorNodes does not include the $contextNode itself.

nodes = ${Search.query(site).nodeType('Neos.Neos:Document').execute()}

Therefore, this gives me all documents inside the Neos Installation, including other sites.