Expected behavior
The label should move back to the center of the select field after deselecting all options.

Actual behavior
The label stays at the top of the select field.

Resources (screenshots, code snippets etc.)
This bug is also reproducable on the demo page:
https://mdbootstrap.com/docs/standard/forms/select/#section-multiselect

How to reproduce:
- Click on the select field and select any option
- Unfocus
- Click on the select field again and deselect all options
- Unfocus again

(The problem source might be that the input element keeps the active class)