this commit aligns timezone parsing logic with DateFormat.Iso8601. Timezone can be provided on a pattern and as ingest parameter. When no timezone is provided on a pattern it is defaulted to UTC or an ingest parameter (if provided).

When timezone is not present in a pattern, but an ingest timezone parameter is provided - a date should be parsed as if it was in that timezone.
Example: pattern "uuuu-MM-dd'T'HH:mm", text "2020-01-01T01:00", timezone: -01:00 should return 2020-01-01T01:00:00-01:00
If the pattern has a timezone and a timezone parameter is provided - a date should parsed with a timezone from input, and then "recalculated" to an ingest parameter
Example "uuuu-MM-dd'T'HH:mm XXX", text "2020-01-01T01:00 -02:00", timezone -01:00 should return 2020-01-01T02:00:00-01:00
relates #38407
relates #51215
closes #63458

backports #63876

• Have you signed the contributor license agreement?
• Have you followed the contributor guidelines?
• If submitting code, have you built your formula locally prior to submission with gradle check?
• If submitting code, is your pull request against master? Unless there is a good reason otherwise, we prefer pull requests against master and will backport as needed.
• If submitting code, have you checked that your submission is for an OS and architecture that we support?
• If you are submitting this code for a class then read our policy for that.