Improve the UX of `FieldManager` field on restart

[TimShilov]

Is your feature request related to a problem? Please describe. As part of #3285 a new FieldManager option was added to the "Confirm Restart" dialog.

I understand why it was added and appreciate it.

However, I would assume that a big portion of k9s users don't really need it, so this extra field adds an unnecessary action to every single restart for a lot of users. Restarts are a relatively frequent operation (at least in my case) and IMO it should be as quick/simple as possible.

Describe the solution you'd like Some options I can think of:

1. Make the confirmation prompt accept the entered value and confirm when "Enter" is pressed (the same action that would happen if "OK" option is selected)? Right now it simply switches focus to "Cancel" button which IMO is counter-intuitive (usually, I believe, "Enter" submits the form).
2. Make it possible to specify the options for this field via config file. This way, anyone who needs to specify custom FieldManager, could specify the options that are applicable to their clusters. If there's no option in config - just use default as before.
3. I'm not very familiar with FieldManager, but maybe there's a way to simply read available field managers from the cluster and only ask to pick one if there are multiple? 🤔

Describe alternatives you've considered

• I've tried to get used to the new confirmation prompt, but failed. It still frustrates me often, as due to muscle memory I keep hitting "Cancel" and have to open it up again to actually select "OK". 😅
• I have tried to look trough the changes in 0.54.0 to see if there are any config changes to address the issue, but couldn't find anything.