Remove deprecated `current-db-time` method (#32686)

* Remove deprecated current-db-time method

* Address PR feedback

* sync-timezone! should handle java.time.ZoneId and java.time.ZoneOffset

* Allow time zone offsets as zone IDs

* Fix tests and suppress clj-kondo on a few forms

* Suppress warning on one more occurrence of db-default-timezone

* Map offset Z to time zone UTC when syncing

* Accept zone offsets, zone ids and strings for h2 and oracle

* Mark snowflake as not supporting report timezone

* Revert "Mark snowflake as not supporting report timezone"

This reverts commit 70b15a60334fda707d695bc6c01621961f1c5aa8.

* Fix report-timezone handling

* Numeric timezone

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Co-authored-by: metamben <103100869+metamben@users.noreply.github.com>
Co-authored-by: Tamás Benkő <tamas@metabase.com>