ssh: Update to OpenSSH 9.5p1

Excerpts from the release notes:

Potentially incompatible changes

• ssh-keygen(1): generate Ed25519 keys by default. [NOTE: This change was already merged into FreeBSD.]
• sshd(8): the Subsystem directive now accurately preserves quoting of subsystem commands and arguments.

New features

• ssh(1): add keystroke timing obfuscation to the client.
• ssh(1), sshd(8): Introduce a transport-level ping facility.
• sshd(8): allow override of Sybsystem directives in sshd Match blocks.

Full release notes at https://www.openssh.com/txt/release-9.5

Relnotes: Yes
Sponsored by: The FreeBSD Foundation

(cherry picked from commit edf8578117e8844e02c0121147f45e4609b30680)
(cherry picked from commit b24ca3caa7524e650550d8a2ee1637e6efcb87f1)