Deprecate GraphQL networkTransactions query?

Should we deprecate this query?
It is not optimized, and contains undefined behaviour (only reads locally and accepts non-network transaction type).

Start by reviewing the GraphQL networkTransactions query and its current callers to confirm the reported lack of optimization and undefined behavior. The issue does not name files or tests, so first establish whether deprecation is wanted and define the expected behavior before implementation. Done requires an agreed decision and scope for any deprecation work.

Written by the indexing model from the issue text.