Prevent the attempt to load the materialdesignicons.css.map file

We are trying to load the css map file for the materialdesignicons.css though we do not have it in our code base.

As this is not needed for us anyway, this ticket is to just prevent the attempt to load it as currently, it is showing up an annoying HTTP 404 error in console.

Steps to verify:

1. Launch the Nuxeo instance installed with NEV in Safari 
eg: https://nev-2021.beta.nuxeocloud.com

2. Open Developer console

3. Access Annotations tab for any document.

4. Observe that the attached error shows up in javascript console

Post fix, this should not show up.