…ons of non-nullable elements (happyproff)

This PR was squashed before being merged into the 4.3 branch (closes #34165).

Discussion
----------

[PropertyInfo] Fixed type extraction for nullable collections of non-nullable elements

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        |

When an annotation is declared as `int[]|null`, it is handled like `(int|null)[]|null`. So array values are also nullable.

Now this behavior is fixed that `int[]|null` is either a collection of integers only or null.

How to reproduce:
```php
class Dummy
{
    /** @var int[]|null */
    public $nullableCollectionOfNonNullableElements;
}

/** @var Type[] $types */
$types = (new PhpDocExtractor())->getTypes(Dummy::class, 'nullableCollectionOfNonNullableElements');

$collectionType = $types[0];
assert($collectionType->isCollection() === true); // OK
assert($collectionType->isNullable() === true); // OK
assert($collectionType->getCollectionValueType()->getBuiltinType() === Type::BUILTIN_TYPE_INT); // OK
assert($collectionType->getCollectionValueType()->isNullable() === false); // FAILED
```

Commits
-------

5e394c4 [PropertyInfo] Fixed type extraction for nullable collections of non-nullable elements