ssh: Clean up bits of the main modal UI (#19604)

This PR main relevant change is removing the logic we had inserted for
keyboard nav scroll as that was unreliable; we need to figure out a
better solution still. I'm also removing the visible on hover behavior
for the scrollbar as that was making us lose the click and drag feature
the component has. Lastly, I added a bit of right-margin in the delete
icon button so that's not too crammed with the scrollbar.

Release Notes:

- N/A

crates/remote/src/ssh_session.rs

@@ -1397,7 +1397,7 @@ impl SshRemoteConnection {
                             check_interval
                         );
                         delegate.set_status(
-                            Some("Waiting for another Zed instance to finish uploading binary..."),
+                            Some("Waiting for another Zed instance to finish uploading binary"),
                             cx,
                         );
                         smol::Timer::after(check_interval).await;