Issues with FunctionsFramework::cloudEvent()

Having issues with FunctionsFramework::cloudEvent() when running in Cloud Functions (but not locally) as documented at https://cloud.google.com/functions/docs/tutorials/pubsub#preparing_the_application.

I'm calling the following:

```php
FunctionsFramework::cloudEvent('eventarc-event-name', 'myFunctionName');

function myFunctionName(\CloudEvents\V1\CloudEventInterface $event)
```

This runs locally, but when I run it on Cloud Run the it tells me I have to hint Google\CloudFunctions\CloudEvent, but if I do that it wants CloudEventInterface instead. Putting either results in the other being required.

```
PHP message: PHP Fatal error: Uncaught LogicException: Your function must have "Google\CloudFunctions\CloudEvent" as the typehint for the first argument in /workspace/vendor/google/cloud-functions-framework/src/CloudEventFunctionWrapper.php:65
```

I can't repeat this locally. FunctionsFramework calls the following, which locally always forces CloudEventInterface, and I can debug this right through to the Reflection check on line 71 of CloudEventFunctionWrapper

```php
public static function cloudEvent(string $name, callable $fn)
{
Invoker::registerFunction($name, new CloudEventFunctionWrapper($fn, true));
}
```

If I do both (which seems probably unintended and wrong anyway), I get the following error:

```
PHP message: PHP Fatal error: Uncaught Error: Call to undefined method ReflectionUnionType::getName() in /workspace/vendor/google/cloud-functions-framework/src/CloudEventFunctionWrapper.php:75 Stack trace: #0 /workspace/vendor/google/cloud-functions-framework/src/FunctionValidationTrait.php(43): Google\CloudFunctions\CloudEventFunctionWrapper->validateFirstParameter(Object(ReflectionParameter)) #1 /workspace/vendor/google/cloud-functions-framework/src/CloudEventFunctionWrapper.php(58): Google\CloudFunctions\CloudEventFunctionWrapper->validateFunctionSignature(Object(ReflectionFunction)) #2 /workspace/vendor/google/cloud-functions-framework/src/FunctionsFramework.php(35): Google\CloudFunctions\CloudEventFunctionWrapper->__construct('dicomwebImport', true) #3 /workspace/index.php(11): Google\CloudFunctions\FunctionsFramework::cloudEvent('transport-reque...', 'dicomwebImport') #4 /workspace/vendor/google/cloud-functions-framework/router.php(37): require_once('/workspace/inde...')
```

I'm not even sure how to proceed here, as this is the officially documented approach, but doesn't appear in the readme for this project at all.

Inizia con CloudEventFunctionWrapper.php, nei controlli di validazione intorno alle righe 65-75, e con FunctionsFramework::cloudEvent(), quindi confronta la firma documentata con il comportamento di Cloud Run e locale descritto qui. Riproduci la validazione del type-hint e il fallimento di ReflectionUnionType; il lavoro è completato quando la firma documentata della funzione CloudEvent viene gestita in modo coerente in entrambi gli ambienti.

Scritto dal modello di indicizzazione a partire dal testo della issue.