[4.2][Bug] Fake subfields do not get saved

[tabacitu]

Bug report

What I did

Tried to edit the number_with_prefix fake field inside Monster, in the new scenarios we've created (Story, Cave, Hero) to test which subfields work inside the relationship field.

What I expected to happen

Fake subfields to work, to get saved.

What happened

Fake fields do NOT get saved when used as subfields:

(A) inside Caves (hasOne) it will not work, but not show any error either

(B) inside Stories (hasMany) it will not work AND show a big fat error

(C) inside Heroes (belongsToMany with extra pivot attributes) I haven't tried it yet since the whole CRUD is broken at the moment

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IMPORTANT: I'm not saying they must work. I'm saying they don't. Not sure we should do anything about this. Because that "anything" probably involves moving the fake field functionality from the CreateOperation and UpdateOperation to a CrudPanel trait. Which will be YET ANOTHER breaking change...

We need to talk about this one, think about it... analyze what's intuitive/useful and how/if we can proceed.

Is it a bug in the latest version of Backpack?

Happening both on 4.2 and on create-all-relations-at-same-time branches.

[tabacitu]

Note - this wasn't a problem in repeatable. Fake fields there don't make sense. But now that we use them as real fields... they kind of do...

[tabacitu]

Fixed in #4129