fix: never let root read the SSH configuration from stdin

A driver gains root with sudo -S and puts the password in front of stdin.
A sudo that does not prompt -- NOPASSWD, a cached timestamp -- leaves it
there, and the cat under sudo wrote it into the drop-in as its first line.
Seen on the first real run (NetOrk/netork#1027): sshd -t rejected the file
and the rollback removed it, but the password was in a 0644 file for a
moment and in the error the caller showed.

The content now goes without privilege to a mktemp file only the login user
can read; root installs that file (mode 644, root-owned) and removes it.
The fake host in the tests prepends the password to every privileged stdin,
as a non-prompting sudo does.

Bumps to 4.5.1. NetOrk/netork#1027, NetOrk/netork#1029

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "napalm-device-types"
-version = "4.5.0"
+version = "4.5.1"
 description = "Abstract device-type base classes for NAPALM drivers"
 readme = "README.md"
 requires-python = ">=3.10"