[CodeQuality] Skip nested value compare in CallbackSingleAssertToSimplerRector

[TomasVotruba]

CallbackSingleAssertToSimplerRector converts a callback() closure with a sole assertSame() into an equalTo() matcher. But equalTo() matches against the whole closure argument, so the conversion is only correct when the asserted value is the plain closure parameter.

When the assert compares a nested value (e.g. $args['label']), converting to equalTo() would wrongly match the entire argument. Now skipped.

->with($this->callback(function (array $args): bool {
    $this->assertSame($args['label'], 'Test Label');

    return true;
}));

Stays untouched (previously wrongly collapsed to ->with($this->equalTo('Test Label'))).

Still converts when the actual value is the whole parameter:

-->with($this->callback(function ($type): bool {
-    $this->assertSame(TextType::class, $type);
-
-    return true;
-}));
+->with($this->equalTo(TextType::class));