Code components: optional properties should not require examples

#3509037: JavaScriptComponent config entities' `examples` and `enum` do not respect the prop's type just landed and made this trivial to fix.

Tests are proving the problem now 👍

This should use ComponentMetadataRequirementsChecker, which will also mean we'll get examples validated in the future automatically, too — thanks to #3508725: ComponentMetadataRequirementsChecker::check() should validate that the example(s) actually match the JSON schema.

1. New constraint validator that calls ComponentMetadataRequirementsChecker — fails in an interesting way!
2. Realize it A) must only run after JsComponentHasValidSdcMetadataConstraintValidator has verified it works — this is not possible in Drupal's Symfony validation constraint setup. So: merge it.

   Then realize B) that it overlaps with \Drupal\experience_builder\Plugin\Validation\Constraint\IsStorablePropShapeConstraintValidator.

Solution: expand JsComponentHasValidSdcMetadata (+ rename) and remove IsStorablePropShapeConstraintValidator. Less precise validation errors, but simpler code. And it even makes this MR a net reduction in LoC!

💁‍♂️ We can work on making the validation errors precisely target the faulty property path value in the config entity later, if there is a need for that. Because the XB code component editor UI does not even allow creating invalid ones — so only people manually modifying JavaScriptComponent config entity YAML exports and then importing them will ever even see these errors.

P.S.: the Implicit conversion from float 3.14 to int loses precision PHP deprecation warning is due to a core bug: \Drupal\options\Plugin\Field\FieldType\ListItemBase::simplifyAllowedValues() uses the value of each list option as an array key. This works fine for strings and ints (both valid array key indices), but not floats. Try running $test = [3.14 => 'test']; on PHP >=8.1 and you'll see the same. I first thought this was caused by #3493070: SDC `enum` props should have translatable labels: use `meta:enum`, but it's not.

Manually tested in the UI, it works:

Before

After

👍