Can't open mobile menu or scrollToTop

[rhizoet]

Is this a BUG REPORT or FEATURE REQUEST?:
bug

What happened:
In mobile mode I can't open the menu. When I click on the hamburger menu nothing happens.
Same for the ScrollToTop Button - but theres the bug in desktop and mobile mode.

In the demo the bugs are also present.

What you expected to happen:
The menu should open and the button should scroll me to the top of the page.

How to reproduce it (as minimally and precisely as possible):
Local install without any configuration and the demo: https://themes.gohugo.io/theme/syna/

Anything else we need to know?:
Nothing special here.

Environment:

• Syna Theme version: Latest commit 94d6a04
• Hugo version: v0.62.0-6608F155/extended
• Others: -

[stp-ip]

Duplicate of #677 as far as I can see.
PR is in flight: #678

[stp-ip]

This should be fixed with #681 in master. Let us know, if anything else comes up. Happy for you to test the latest change. Adding tests for this regression as well.