Remove the unused MLKEM1024_SHARED_SECRET_BYTES

This appears to perhaps have been a pasto and is confusing
to consumers of this API.

You share the same size secret with any mlkem

Change-Id: I6ddfa21b4f8d293f990064a2a54cda9ba6119d5a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/70527
Commit-Queue: Adam Langley <agl@google.com>
Auto-Submit: Bob Beck <bbe@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Bob Beck <bbe@google.com>

include/openssl/mlkem.h

diff --git a/include/openssl/mlkem.h b/include/openssl/mlkem.h
index 34fdd9d..e2abaa9 100644
--- a/include/openssl/mlkem.h
+++ b/include/openssl/mlkem.h
@@ -161,10 +161,6 @@
 // public key.
 #define MLKEM1024_PUBLIC_KEY_BYTES 1568
 
-// MLKEM1024_SHARED_SECRET_BYTES is the number of bytes in the ML-KEM-1024
-// shared secret.
-#define MLKEM1024_SHARED_SECRET_BYTES 32
-
 // MLKEM1024_generate_key generates a random public/private key pair, writes the
 // encoded public key to |out_encoded_public_key| and sets |out_private_key| to
 // the private key. If |optional_out_seed| is not NULL then the seed used to