Convert content ids to content types

Converts a list of content ids into their associated content types. This is useful for users migrating from v1 to v2 who may have stored just content ids without their associated type. This will return types as they should be used in v2. Notably, this will return inline-comment for inline comments and footer-comment for footer comments, which is distinct from them both being represented by comment in v1.

Permissions required: Permission to view the requested content. Any content that the user does not have permission to view or does not exist will map to null in the response.