Fixed filter attribute deselection from within the filters page

[fkloes]

Description

It's now possible again to deselect all filter attribute values from within the filters page. Before is wasn't possible to deselect those attribute values which where already set when the filter page was entered.

Type of change

• [ x ] Bug Fix 🐛 (non-breaking change which fixes an issue)
• [ ] New Feature 🚀 (non-breaking change which adds functionality)
• [ ] Breaking Change 💥 (fix or feature that would cause existing functionality to not work as expected)
• [ ] Polish 💅 (Just some cleanups)
• [ ] Docs 📝 (Changes in the documentations)
• [ ] Internal 🏠 Only relates to internal processes.

How to test it

• open the filter page from a product list (e.g. a category)
• select one or more filter attribute values and apply the filters
• open the filter page again and deselect all attribute values