dual alg: add ML-DSA test, and misc cleanup.

[philljj]

Description

Add a dual-alg ML-DSA + ECDSA test, and some miscellaneous cleanup:

• Add test_dual_alg_ecdsa_mldsa() to tests/api.c (Based on ecdsa + mldsa demo here: https://github.com/wolfSSL/wolfssl-examples/tree/master/X9.146).
• Add missing comments to ASN functions, and trim line lengths.
• Remove unused WOLFSSL_LOCAL function wc_ConfirmAltSignature().
• Add missing wc_MlDsaKey_*KeyToDer() define to wolfssl/wolfcrypt/dilithium.h

Testing

./configure --enable-experimental --enable-dual-alg-certs --enable-dilithium --enable-debug && make
./tests/unit.test --list | grep dual_alg
338: test_dual_alg_support
339: test_dual_alg_ecdsa_mldsa
./tests/unit.test -339

[philljj]

retest this please