cockpit: adjust key fingerprint matching for openssh-10.2p1

The regex adjustment in 93122ef wasn't enough, it
matches to broadly for openssh-10.2p1 as the host key no longer ends
with an dot but with an newline.

New prompt:
```
ED25519 key fingerprint is: SHA256:xD6UcDvVDpRNIKew3CVJtajlPujToVumgISXdunBUfY
This key is not known by any other names.
```

Old prompt:
```
ED25519 key fingerprint is SHA256:YDOcdZxLSmDEM2xGgyAs5lFUbUXK2F8zi0yRbpiA2oo.
This key is not known by any other names.
```

Author: jelly

src/cockpit/beiboot.py

@@ -171,7 +171,10 @@ async def do_askpass(self, messages: str, prompt: str, hint: str) -> Optional[st
 
         # FIXME: is this a host key prompt? This should be handled more elegantly,
         # see https://github.com/cockpit-project/cockpit/pull/19668
-        fp_match = re.search(r'\n(\w+) key fingerprint is:? ([^.]+)\.', prompt)
+        # Since openssh 10.2p1-1 the host key prompt changed:
+        # - now includes a colon after "key fingerprint is"
+        # - does not end on a dot but a newline (likely for easier copy-pasting
+        fp_match = re.search(r'\n(\w+) key fingerprint is:? ([^.\n]+)', prompt)
         # let ssh resolve aliases, don't use our original "destination"
         host_match = re.search(r"authenticity of host '([^ ]+) ", prompt)
         args = {}