Fix fenrir858-859

[yosuke-wolfssl]

Description
This PR contains 2 commits:

1. Add wc_HashFree() into BuildUserAuthRequestRsa (line 14128), BuildUserAuthRequestRsaCert (line 14362), BuildUserAuthRequestEcc (line 14572), and BuildUserAuthRequestEccCert (line 14812) in src/internal.c if wc_HashInit() is successfully returned.
2. Add Ed25519 key clean up into FreePubKey() in src/internal.c. Also, add keyAllocated flag once the key is successfully imported in ParseEd25519PubKey().

[Copilot]

Pull request overview

This PR addresses resource cleanup issues related to hashing during user-auth request signing, and fixes Ed25519 public key lifecycle handling in src/internal.c.

Changes:

• Ensure wc_HashFree() is called when wc_HashInit() succeeds in multiple user-auth request builders (RSA/RSA-cert/ECC/ECC-cert).
• Track successful Ed25519 public key import via keyAllocated and add Ed25519 cleanup in FreePubKey().

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[Copilot]

Pull request overview

This PR addresses resource cleanup issues in wolfSSH’s internal key parsing and user-auth request signing paths, aiming to fix reported fenrir findings.

Changes:

• Ensure wc_HashFree() is called after successful wc_HashInit() in multiple BuildUserAuthRequest* signing helpers.
• Track Ed25519 public-key import success via keyAllocated and add Ed25519 cleanup in FreePubKey().

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