add-forge-now: Improve conditional so incremental listing is delayed

Otherwise, listing types without a 'list-%-full', 'list-%-incremental' pattern (e.g list-cgit, ...) are systematically delayed 1 day the first time the add-forge-now schedules them.

We've got a few of them [1]

[1]

2023-04-12 11:32:26 softwareheritage-scheduler@belvedere:5432 λ select type from task_type where type not like 'list-%-%' and type like 'list-%';
+----------------+
|      type      |
+----------------+
| list-pypi      |
| list-opam      |
| list-cgit      |
| list-cran      |
| list-packagist |
| list-arch      |
| list-aur       |
| list-crates    |
| list-bower     |
| list-conda     |
| list-cpan      |
| list-golang    |
| list-hackage   |
| list-nixguix   |
| list-nuget     |
| list-pubdev    |
| list-puppet    |
| list-rubygems  |
+----------------+
(18 rows)

Time: 20.117 ms

Refs. swh/infra/sysadm-environment#4845 (closed)