Related to #127521 and, in the same vein, the LucenePushdownPredicates don't use FieldAttributes#fieldName here but just the name method. For field attributes representing converted union types, like $$field$converted_to$long the actual field name (field) is different from the attribute name, which means that this doesn't correctly apply to union types.

I tried to quickly fix this but this regresses the csv tests for union types, which is consistent with some observations by @fang-xing-esql in #127797 that union types don't work correctly with attribute pushdowns.