fix(signin): set email sign-in input to "email" & "required"(#4352)

* fix(core\pages\signin.tsx): set type of built-in email sign-in input to email for browse validation
* fix(core\pages\signin.tsx): add required attribute to built-in sign-in email input

Co-authored-by: Lluis Agusti <hi@llu.lu>

packages/next-auth/src/core/pages/signin.tsx

@@ -123,10 +123,11 @@ export default function SigninPage(props: SignInServerPageParams) {
                 <input
                   id={`input-email-for-${provider.id}-provider`}
                   autoFocus
-                  type="text"
+                  type="email"
                   name="email"
                   value={email}
                   placeholder="email@example.com"
+                  required
                 />
                 <button type="submit">Sign in with {provider.name}</button>
               </form>