Compatibility issues with webform (skip validation of required fields)

When hide_submit is installed it's possible to circumvent the webform validation, resulting in missing data from required fields.

Steps to reproduce:

1) Install hide_submit and webform.
2) Create a new webform with a page break, a grid component and another page break
3) Mark the grid component as required
4) Load the form and press 'next' to go to the grid.
5) Press 'next' from the grid without entering any input. The HTML5 validation kicks in and ask you to fill out the grid questions.
6) Press 'previous'. You are now sent to the last page having skipped the validation of the required fields.

What I think happens is that the form triggering element is cheated to believe that we have pressed 'next', and isn't updated properly when the hide_submit script runs. Apparently there is no server validation on grid questions in webform (select components, for example, trigger the form_set_error).

I believe that this is coupled to this long standing issue in drupal core: https://www.drupal.org/node/2628962 (which is also reported by me.)