[8.x] Allow method typed variadics dependencies

[LeoColomb]

This reasonably simple change would enable to use variadic for DI when calling a Callable, in addition to class resolution.

Here is an example reusing the objects from the documentation:

$app->bind(Filter::class, function ($app) {
    return [
        $app->make(NullFilter::class),
        $app->make(ProfanityFilter::class),
        $app->make(TooLongFilter::class),
    ];
});

$app->call(function (Logger $logger, Filter ...$filters) {
    //                               ⏫ this is currently unsupported
});

I think this can be beneficial for the following reasons:

• you may have a callable or a class method that receives an array of typed objects, the same way documentation explains for constructors;
• there are cases when resolution for constructors only is not sufficient unless over objectifying things.
  • see my example below.
• this addition partially mitigates the need of contextual binding for methods ([7.x] Allow Contextual Binding outside of constructors #30542):
  • for variadic, the enforced specific context is no more required, they can be use with classical bindings.
  • improve consistency across DI
• backward compatible, as it only match variadic when a type is specified (maybe array of arrays type can conflit? not even sure it is natively supported)
• it is not very easy to implement the suggested behavior via a package

Example of a case where a constructor cannot handle it

• Not allowed:

  public function __construct(public Logger $logger, Filter ...$filters, Whatever ...$objects)
  { //                                                                   ⏫ this is illegal
      $this->filters = $filters;
      $this->objects = $objects;
      $this->method();
  }  
  
  public function method()
  {
      // attributes consumer
  }

• Naive remedy:

  public function __construct(public Logger $logger, Filter ...$filters)
  {
      $this->filters = $filters;
      App::call([$this, 'method']);
  }
  
  public function method(Whatever ...$objects)
  {
      //
  }

[taylorotwell]

Had to make one small change for backward compatibility with existing code.