Fix ChoiceField when entity is enumType and no choices were given

[Uplink03]

Fix ChoiceField when entity is enumType and no choices were given explicitly

Bugs

BUG: if setChoices is not called on the ChoiceField, and the backing entity field is an Enum, the dropdown displays 0, 1, 2, 3, etc., because the $choices array ends up like this:

array:2 [
  0 => App\Enum\ProjectTypeEnum {
    +name: "PHP"
    +value: "php"
  }
  1 => App\Enum\ProjectTypeEnum {
    +name: "DOCKER"
    +value: "docker"
  }
]

BUG: Symfony Forms attempts to convert the enum to string.

Fixes

Fix the ChoiceConfigurator

This PR fixes the ChoiceConfigurator to behave as if ->setChoices(MyEnum::cases()) were called.

Related to commit 65a422b of PR #5879 by @SerheyDolgushev

Fix the forms

Although closed, bug #5641 was not addressed by PR #5879. Without the change suggested by the original reported, the following errors are thrown:

The EDIT action of a CRUD that contains a ChoiceField with an enum:

Object of class App\Enum\ProjectTypeEnum could not be converted to string

The Create action of a CRUD that contains a ChoiceField with an enum (the NEW page doesn't complain until submitted):

Expected argument of type "App\Enum\ProjectTypeEnum", "string" given at property path "type".

[javiereguiluz]

@Uplink03 thanks for this bug fix. I'm sorry I managed the handling of enums in choice fields so badly 😐