Currently, `RemoteEntry::SshConfig` for `ssh_config_servers` initializes
on every render. This leads to side effects like a new focus handle
being created on every render, which leads to breaking navigating
up/down for `ssh_config_servers` items.

This PR fixes it by moving the logic of remote entry
for`ssh_config_servers` into `default_mode`, and only rebuilding it when
`ssh_config_servers` actually changes.

Before:


https://github.com/user-attachments/assets/8c7187d3-16b5-4f96-aa73-fe4f8227b7d0

After:


https://github.com/user-attachments/assets/21588628-8b1c-43fb-bcb8-0b93c70a1e2b

Release Notes:

- Fixed issue navigating SSH config servers in Remote Projects with
keyboard.