Allow custom cypher queries on refresh_schema()

[dvirm-cr]

There is an issue in my case where large schema (many properties) cause the token allowed to exceed.
I was able to bypass that using rel_query returns

RETURN {type: nodeLabels, properties: properties[0..5]} AS output

this leads to allowing custom cypher queries to be supported - I'm sure there are other cases where this can be helpful
can you add me as contributor so I can open a PR?
thx