bug(date-adapter): Misleading JSDoc for createDate returns type

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

(I don't know if it sould be a bug or docs-bug, because it's about JSDoc that not available in the material doc
website, so I couldn't join a link to the doc and create a docs-bug issue).

In the JSDoc of the DateAdapter createDate method, the returns tag indicates that :
@returns The new date, or null if invalid.
But the method returns type is just D, not D | null so it can't be null.
And in the different implementations of the date adapter, when the params are invalid, an error is throws, not a null return.

### Reproduction

This bug is more a docs-bug, but date-adapter JSDoc is not directly available from the doc website, so I couldn't join a link to create a docs-bug.
The components/src/material/core/datetime/date-adapter.ts, line 110

### Expected Behavior

the returns tag indicates that an error is throws when invalid

### Actual Behavior

the returns tag indicates that null is returned when invalid

### Environment

no specific env

Inizia da components/src/material/core/datetime/date-adapter.ts intorno alla riga 110 e controlla lo JSDoc del metodo createDate insieme al tipo restituito dichiarato. Verifica il comportamento documentato per gli input non validi rispetto alla descrizione del metodo e alle implementazioni menzionate nell’issue. Il lavoro è completato quando lo JSDoc descrive accuratamente il tipo restituito e cosa accade quando l’input non è valido.

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