To achieve this this commit does the following:
- create a new `groups field, ideally we would have reused the existing group field, but many automations now have the expectation that this field will return a group id and not an array of group ids, which makes it a dangerous change
- alter the code in `post_created_edited` to use this new groups field and change the logic to use an array
- migrate the existing group fields post_created_edited automations to change name from `restricted_group` to `restricted_groups`, the component from `group` to `groups` and the metadata from `{"value": integer}` to `{"value": [integer]}`
The automation plugin has 4 custom field types that are array typed. However, array typed custom fields are deprecated and should be migrated to JSON type.
This commit does a couple of things:
1. Migrate all four custom fields to JSON
2. Fix a couple of small bugs that have been discovered while migrating the custom fields to JSON (see the comments on this commit's PR for details https://github.com/discourse/discourse/pull/26939)
