Allow deselection of "send fleet" command by pressing F again

[minitauros]

Is your feature request related to a problem? Please describe.

When I press F, I can send my whole fleet somewhere. Sometimes I accidentally press F, and then I cannot NOT send my fleet somewhere.

Describe the solution you'd like

Allow pressing F again to stop the "send fleet" command.

Describe alternatives you've considered

I don't think there is a better alternative.

[github-actions]

Hi @minitauros, thanks for opening this issue. It hasn't been approved by a maintainer yet — we'll get back to you shortly to either milestone it (approval) or close it.

— Automated. See CONTRIBUTING.md.