fix: options page doesn't work on Firefox for Android

[WofWca]

A review said this, and I have managed to reproduce: https://addons.mozilla.org/addon/jump-cutter/reviews/1871616/

I don't know what's this caused by. Here's how to debug on Android.

Also need to see if it's related to #120.

Related: #65.

[WofWca]

The problem seems to be on this line:

https://github.com/WofWca/jumpcutter/blob/5f434fdae08115e834e51cd0d0a414bfb0816433/src/entry-points/options/App.svelte#L53

It says ".commands is undefined"

[WofWca]

Fixed in bd85951bbc3b54193483626deb47ac6c0a1de231