Issue: Collapsing problem still happen on offline channel

[Mishasama]

• Fixed collapsing: the extension is force-stopped from running on special pages

Originally posted by @Ephellon in #37

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How to repoduce:

1. The streamer is offline
2. Go to the channel homepage
3. Trigger the small player at the top of the page to automatically play a VOD
4. The chat window that shouldn't have appeared popped up on the right