I want to change the Home Assistant integration to use my Production HA rather than my Test instance

Not the same issue, but I recently had this problem - Home Assistant stopped working and disappeared from Add Integrations? - I could not get HA to uninstall and reinstall on the remote so I ended up wiping out the remote and restoring a backup. At that point, I was able to add the HA integration back in and reconfigure it.

I hope you find a much easier, cleaner way to do this! But worst case maybe you can go the nuclear route.