Forbid selection of same track endpoint in multi ports switch

[bloussou]

What happened?

This shouldn't be possible :

Port A and Port B2 have the same track extremity id (same track and different extremities is OK for a loop).

What did you expect to happen?

To be decided (tick what is necessary).

1. Front shouldn't allow selection of the same track extremity:

• ✅ for the same switch > forbid this : able to select, warn user immediately, forbid save
• ❌ on any switch port (even other switch) > Not required currently

2. Editoast should trigger a warning or an error to say that the track extremity is used multiple times on switch ports:

• ✅ on the same switch > add specific error (SelfOverlappingSwitch)
• ✅ on any switch > already done (Overlapping of switches)

3. Core:

• ✅ check that loading an infra fails with SelfOverlappingSwitch (and add this if needed)

How can we reproduce it (as minimally and precisely as possible)?

try to create a 3 ports switch with two tracks

What operating system, browser and environment are you using?

Firefox

OSRD version (top right corner Account button > Informations)

staging b59698b