GitlabUiFormBuilder#submit: Consider passing additional options to Pajamas::ButtonComponent

This came up during Pajamas Migration Day: December 2, 2022 (gitlab-org/gitlab-services/design.gitlab.com#1448 - closed):

When I make the change, the Pajamas buttons are left-aligned and doesn’t fill up the entire space. Should I also make changes such that it looks like before where it fills up the entire space?

What if we add the class btn-block as per the Full width button example?

Ideally, we wouldn't need to specify a class, and instead use the block option of Pajamas::ButtonComponent:

= f.submit _('Resend'), pajamas_button: true, block: true