fix: align OCB3 decrypt length checks with encrypt

[radik878]

Previously OCB3 decryption accepted plaintext and associated data of exactly max_len bytes, which could lead to out-of-bounds access in the precomputed L table and a panic instead of a clean error for boundary-size inputs.
Tightened the max_len checks in decrypt_inout_return_tag to match encryption, rejecting inputs with length >= max_len for both plaintext and associated data so that large inputs consistently return an error instead of panicking.