Webform redirects to incorrect page due to cache

Problem/Motivation

When someone visits a form on /en/form/contact?utm_content=webform_test and afterwards someone visits /en/form/contact the action will still redirect us to /en/form/contact?utm_content=webform_test.

Steps to reproduce

1. Make sure no caches are disabled
2. Ignore parameter utm_content
3. Clear cache
4. Visit form on /en/form/contact?utm_content=webform_test
5. Visit form on /en/form/contact
6. Submit form and get redirect to the page with query parameter

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes