Align Remote function classes to ModelTrainer: Include training_plan_arn to remote function classes @remote decorator and RemoteExecutor

**Describe the feature you'd like**
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ModelTrainer and Estimator classes currently support training_plan_arn, in order to run training workload by leveraging the instances included in the plan. This functionality is not currently available with remote function classes, which is adopted by customer to start prototyping workloads on Amazon SageMaker.

**How would this feature be used? Please describe.**
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```
@remote(
...
training_plan_arn="arn.1234....."
)
def train(args):
pass
```

**Describe alternatives you've considered**
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There are no alternative solutions

**Additional context**
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Inizia confrontando il modo in cui ModelTrainer ed Estimator accettano e usano training_plan_arn, quindi traccia i percorsi di @remote decorator e RemoteExecutor per una configurazione equivalente. Definisci il flusso previsto per l'ARN dagli argomenti del decorator fino all'esecuzione remota e aggiungi una coverage che dimostri che una remote function può essere avviata con il training plan specificato.

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