[Bug] xExtension-ColorfulList: JavaScript error on pages that have no feed articles

[math-GH]

ping @shinemoon

Extension: xExtension-ColorfulList

FreshRSS version: current 1.22.2-dev edge

JavaScript error in the browser console (tested with Firefox 120 on Win10)

Error appears on every page, that does not show the feeds.
No error: normal view
Error: subscription manage page. Or: Extension page

[shinemoon]

Fix created as above... please help to check. thx.

[math-GH]

fine