Add support for time types without seconds

[toby-griffiths]

Previously, if you try to use this guesser with a Time field without seconds, this fails because it doesn't take the withSeconds parameter into consideration.

Now, this will add input_format = 'H:i' if withoutSeconds = true.

I cannot see where the tests are for this, so have not written one, but please advise if there is somewhere I can add one.

[GromNaN]

Thanks for your Pull Request! We love contributions.

However, you should instead open your PR on the main repository: https://github.com/symfony/symfony

This repository is what we call a "subtree split": a read-only subset of that main repository. We're looking forward to your PR there!