For DoH and DoT listeners, a reconfiguration event triggers a creation
of a new 'SSL_CTX' TLS context, and a destruction of the old one.
The network manager, though, keeps using the old context which causes
errors.
During interface scanning, when a matching existing interface is found,
reuse it only when it doesn't have a TLS context, otherwise shut it down
and recreate with a new TLS context.
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