column_encryption_policy is checked in reading every single value in decode_val()

[mykaul]

There's no point in checking a global policy for every single value decoding, not for every row decoded.

Please adjust the code to only check it once per recv_results_rows() call - decode_row() should be defined either as is today with column_encryption_policy enabled, or much simpler without all those extra checks.

[mykaul]

drivers team - please ignore - me playing with CoPilot - let it do the work.