Schema sync does not properly count and list multi-label nodes

The schema sync process does not properly count nodes that have multiple labels or types. It will also not list out all node labels.

I originally saw this issue in openCypher connection, but it most likely exists for all connections.

## Potential cause

* The schema sync count uses the first label instead of all labels
* The schema sync attribute discovery only creates a vertex config for the first label

## Related issues

* #1194
* #746

Start with the schema sync process for the openCypher connection and trace node counting and attribute discovery across connections. Check how nodes with multiple labels or types are handled, then verify that counts include all labels and that every label is listed with its own vertex configuration.

Written by the indexing model from the issue text.