Set RSA explicitly | refs #38669

Since openssh 9.5p1 the default type is ed25519 which is not yet
supported by MirisManager.

To avoid incompatibility and as RSA 4096 bits is secure we stay on RSA
for now.

Ref:

    openssh/openssh-portable@e1c284d

mm_client/lib/ssh_tunnel.py

@@ -37,7 +37,7 @@ def get_ssh_public_key():
     else:
         logger.info('Creating new SSH key: "%s".', ssh_key_path)
         p = subprocess.Popen(
-            ['ssh-keygen', '-b', '4096', '-f', str(ssh_key_path), '-N', ''],
+            ['ssh-keygen', '-t', 'rsa', '-b', '4096', '-f', str(ssh_key_path), '-N', ''],
             stdin=subprocess.PIPE,
             stdout=subprocess.PIPE,
             stderr=subprocess.STDOUT