[DX] Adding a helpful error message to the ResetPasswordHandler

[mamazu]

Q	A
Branch?	master
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	-
License	MIT

Before:

Uncaught PHP Exception Webmozart\Assert\InvalidArgumentException: "Expected a value other than null." at /var/www/sylius/vendor/webmozart/assert/src/Assert.php line 2060

After:

Uncaught PHP Exception Webmozart\Assert\InvalidArgumentException: "No user found with reset token: <TOKEN>" at /var/www/sylius/vendor/webmozart/assert/src/Assert.php line 2060

Maybe we also should have a check in the codestyle that finds all other occurrences, where a error message is missing.

[SirDomin]

Thank you, @mamazu! 🎉