[Java][FlightRPC] FlightSQL error: 'Parameter ordinal out of range' executing a prepared stmt with params

Hey again

I'm getting a 'parameter ordinal 1 out of range' error trying to set a parameter on the returned AvaticaPreparedStatement. Repro:

• Open a FlightSQL JDBC connection
• conn.prepareStatement with a SQL query containing params (e.g. INSERT INTO users (id, name) VALUES (?, ?))
• `ps.setString(1, "foo")` -> above error, thrown from AvaticaPreparedStatement.getParameter(int)

I had a bit of a dig to try to identify a potential cause:

• the Meta.Signature passed to the AvaticaPreparedStatement on creation has an empty parameter list - this is what causes the out-of-bounds error.
• in ArrowFlightMetaImpl.prepare, it calls newSignature, but this only takes the SQL query, and so newSignature creates the signature with the empty list. The call to ArrowFlightSqlClientHandler.prepare happens on the line after - could we pass the param Schema from this result to newSignature?

Let me know if I can help narrow this down further or help with the fix

James