[SA] Add space platform interrupt condition "On a planet"

[Hares]

TL;DR

Add a new interrupt-only condition "(not) on a planet", similar to the one with the train stops.

Why?

• This is similar to condition "Circuit condition: <planet> == 3" with enabled "Read moving from" & "Read moving to", but more obvious and does not require setup
• Consistency with the train interrupts