Fix minor issues

[yosuke-wolfssl]

This PR fixes the following minor issues:

• In DoUserAuthInfoRequest(), Fix the accesses to ssh->ctx->heap and ssh->authId inside NULL check
• In wolfSSH_ReadKey_file(), Fix wrong argument of WFCLOSE()
• In FingerprintKey(), Fix Trailing Padding Check
• Fix AlgoListSz() for empty string input
• Fix the processing order in BundlePacket() for bounds Check

Addressed by f_215, f_216, f_406, f_407, f_408

[Copilot]

Pull request overview

This PR addresses several small correctness issues in wolfSSH’s core packet/auth handling and client tooling by tightening bounds checks, fixing an invalid filesystem-close call, and preventing invalid memory accesses.

Changes:

• Fix file closing in wolfSSH_ReadKey_file() by passing the correct filesystem context to WFCLOSE().
• Harden parsing/auth flow: handle empty algorithm-list strings safely and avoid dereferencing ssh->ctx / setting authId on failure in keyboard-interactive auth.
• Correct ordering and bounds checks in packet bundling and fix a trailing Base64 padding check in fingerprint formatting.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/ssh.c	Fixes WFCLOSE() call in wolfSSH_ReadKey_file() to use the correct filesystem argument.
src/internal.c	Adds safe empty-string handling in AlgoListSz(), corrects keyboard-interactive auth heap/authId handling, and reorders MAC buffer zeroing after bounds checks in BundlePacket().
apps/wolfssh/common.c	Fixes trailing Base64 padding removal logic in FingerprintKey() without out-of-bounds access.

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