[BUG] time zone checks for from_json are too broad and do not follow JsonScan

[revans2]

Describe the bug
The code that checks time zones for JsonOptions, which is what is used by JsonScan looks specifically if a timestamp is being read, but there are other more generic checks for JsonToStructs where it just looks if a non-utc timezone is set or not. This makes it so we fall back for all situations where there is an unsupported timezone set, even if that timezone would never be used.