[C++][FlightRPC] Use IRD precision/scale defaults with ARD override in SQLGetData

[HyukjinKwon]

Describe the enhancement requested

arrow/cpp/src/arrow/flight/sql/odbc/odbc_impl/odbc_statement.cc

Lines 746 to 748 in 8fc54a3

	// TODO: Get proper default precision and scale from abstraction.
	int precision = 38; // arrow::Decimal128Type::kMaxPrecision;
	int scale = 0;

This was introduced by ed36107

Component(s)

C++