* pie percent switch

* review

* Migrate to card viz-settings v.2 (#26798)

* Migrate to card viz-settings v.2

This uses the new :pie.percent_visibility key (an enum) instead of a
collection of booleans

[#26776]

* Move to def-json-migration

* Don't migrate empty values

* fix specs

Co-authored-by: Tim Macdonald <tim@metabase.com>