When adding a contact group to Sequence recipients, all contact columns should be added to the recipient table.

Feature request
When selecting a contact group in the sequence recipients editor, all the contact card columns should be added to the sequence recipient table.

Current behavior
When adding a contact group to the sequence recipient table, only the contact email is imported to the table.

Background
More often than not, using variables like {{recipient.first_name}} would be nice. This worked before, but does not anymore by design, and we are limited to {{sequence}} variables, which can be imported into a sequence by downloading all contacts as .csv, import to a sheet editor, manually filtering out the relevant contact group, export as csv again, and import the csv to the sequence recipient table.

Implementing the request the feature would allow for using {{sequence.first_name}} easily, without the current export/import/filter/export/import hassle.