Remove unneeded placeholder from zone's scope select (#16226)

| Q               | A
|-----------------|-----
| Branch?         | 1.12 <!-- see the comment below -->
| Bug fix?        | a bit
| New feature?    | no
| BC breaks?      | no
| License         | MIT

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src/Sylius/Bundle/AddressingBundle/Form/Type/ZoneType.php

@@ -52,7 +52,7 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
                 ->add('scope', ChoiceType::class, [
                     'choices' => array_flip($this->scopeChoices),
                     'label' => 'sylius.form.zone.scope',
-                    'placeholder' => 'sylius.form.zone.select_scope',
+                    'placeholder' => null,
                     'required' => false,
                 ])
             ;

src/Sylius/Bundle/AddressingBundle/Resources/translations/messages.en.yml

@@ -34,6 +34,5 @@ sylius:
             scopes:
                 all: All
             select: Select
-            select_scope: Select scope
         zone_member:
             select: Select