Unnecessary scrollbar in "Template" import overlay.

Moved from ZBXNEXT-7951 20th sub issue.
Issue seems to be present only on master branch.

Steps to reproduce:

1. Open /templates.php;
2. Open browser console(ctrl+shift+J);
3. Press on "Import" button;
4. Import any template export file, which contains some information;
5. Observe that on the right side, there are two scrollbars;

Result:

Expected:
Most right scrollbar is not present at all.