remove json column v4 format writers

[clintropolis]

Description

Removes the ability to write JSON columns in the older version '4' format, leaving only the latest current version, '5', as the only option. (Internally it isn't really v5, rather v0 of the 'auto' format, but it is branded as v5 for the sake of continuity).

I have left the structures to control which version is written added in #14955, in the event we need to introduce any newer versions in the future, we just only allow v5 right now.

Release note

JSON columns can no longer be written in the older V4 format, the current latest version, V5, is the only version which can be written to new segments. This means both the formatVersion of a JSON column spec on JSON based ingestion specs, e.g.

          {
            "type": "json",
            "name": "someColumn",
            "formatVersion": 5
          }

and druid.indexing.formats.nestedColumnFormatVersion in runtime.properties only allow 5.

All older version of JSON columns can still be read and queried just fine, this change just prevents writing new segments in the older format.