Steps to reproduce

1. Log in to back office.
2. Go to Media / Images.
3. Switch tab to 'Sub-items'
4. Click on 'Upload' button.
5. Upload a lot of files.

Actual result:

Multi-file upload modal increases its height to the edge of the browser instead of displaying scroll.

Expected result:

Multi-file modal should be limited to e.g. 10 rows and then scroll should be available.