Remove honk_recursion flag

[lucasxia01]

Introduced by AztecProtocol/aztec-packages#6719.

The honk_recursion flag tells the acir code which recursion constraint to lay down. This flag is currently based on whether we're using ultra honk to prove, but a proper fix would encode this through the opcode.

[lucasxia01]

Since the creation of this issue, honk_recursion has become used in different contexts. #1326 is the new issue for these contexts.

This above PR will close this issue in the context of using it for generating the ACIR.