sortBy doesn't work in MultiDropdownList anymore.

We use Reactiveasearch pointing to ElasticSeacrh 6.x
Recently we migrated ElasticSeacrh 6.8 to ElasticSeacrh 8.x
Now sortBy doesn't work in MultiDropdownList . I have to comment it in order I see data in MultiDropdownList.

**Describe the bug**

**To Reproduce**

Steps to reproduce the behavior:

**Expected behavior**

**Screenshots**

**Desktop (please complete the following information):**
- OS: [e.g. iOS]
- Browser [e.g. chrome, safari]
- Version [e.g. 22]

**Smartphone (please complete the following information):**
- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Additional context**