[Validator] Skip validation when email is an empty object

[acrobat]

Q	A
Branch?	3.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Tickets
License	MIT
Doc PR

When the value passed to the email validator is an empty object the validator is still called and will mark the value as invalid. The object should be skipped in this case, as it is also done in the UrlValidator

symfony/src/Symfony/Component/Validator/Constraints/UrlValidator.php

Lines 59 to 62 in bfdbb24

	$value = (string) $value;
	if ('' === $value) {
	return;
	}

[fabpot]

Thank you @acrobat.