Unfortunately, deleting a playlist from your Fire Stick is not currently a feature. However, as mentioned, when making changes to your Pandora account from another device, like the web, any changes made should carry over.
However, it sounds like the changes you've made are not being reflected on your Fire TV. I'm currently investigating if there is another issue occurring that is preventing these changes from appearing on your Fire TV.
While I can confirm that the playlist 'Autumn by LJ' has been removed from your collection on my end. I'm not able to confirm if it still appears on your Fire TV.
When signing out, this will force the app to refresh and may help. Let me know how it goes.
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