lmr: front: catch missing fields and adapt warning message

[axrolld]

Description

Some fields can be left empty and the simulation button does nothing. We need to catch empty fields and warn the user.

AC

• If one of the following fileds is not filled in, the warning box pops up above the button Obtenir la simulation when the user clicks it only (not before). The button Obtenir la simulation slides down, and if it gets out of the screen, there should be an automatic scroll to see the warning message entirely and the simulation button.
  • traction engine
  • consist total weight
  • consist total length
  • consist max speed
  • CI of origin/destination
  • departure or arrival time

[thibautsailly]

I uploaded the mockup in the wrong issue, following a mislabelling in Sketch. Sorry for the misunderstanding and for the potential wasted time, I'll double check before posting from now on!
Deleting the uploaded mockup to prevent more confusion.

[axrolld]

There's this bug currently : it's possible to run a simulation with plenty of wrong values. I guess closing this issue will solve this, isn't it @Caracol3 ?

[Caracol3]

It's not clearly stated in the issue, but I think it would be logical to prevent the calculation when there are invalid values, rather than just displaying an informative message.

[axrolld]

Hm, you're right, the issue is actually just mentionning empty fileds. What do you think about blocking invalid ones too ? Should i open a new issue ?