What does this implement/fix?

This fixes FTL restarting for every (!) config change when webserver.threads = 0 and any other config setting is changed, e.g., any of the debug flags out of which none should be triggering a full restart of FTL.

This bug is part of v6.0.4. It is a regression of 2aeccfb. I'm not aware of any reports out in the wild. I furthermore added logging for the particular reason a restart was necessary.

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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