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