🚀 Feature: more accurate email validation at sign in and sign up

### 🔖 Feature description

The sign in and sign up forms validate the email address:

When passing without the ending, i.e. ".com", the validation is missing and the form is sent to the server, which then validates:

The email input could already validate against the full accurate email format.

### 🎤 Pitch

As the email format will be validates after sending the form anyways and there exists a form input validation in the frontend, it could be extended with the full email format validation including ".com" endings.

### 👀 Have you spent some time to check if this issue has been raised before?

- [X] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [X] I have read the [Code of Conduct](https://github.com/appwrite/appwrite/blob/HEAD/CODE_OF_CONDUCT.md)

Inizia individuando i campi di input dell’e-mail per l’accesso e la registrazione, insieme alla relativa validazione frontend esistente. Conferma il comportamento attuale con un indirizzo privo della terminazione del dominio, quindi aggiorna la validazione in modo che rifiuti quell’input prima dell’invio e verifica che i moduli continuino ad accettare indirizzi e-mail completi.

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