vault/assets: Fix cooking task creation when there is a pending one
When requesting a vault cooking creation but there is already a pending one for the same SWHID, ensure task creation modal is displayed as previously an error was erroneoulsy reported in the Web UI.
Under the hood, no new cooking task will be created but the pending one will be displayed in the vault UI. Nevertheless the email possibly submitted by the user in the modal will be added to the list of emails to notify by the vault backend.
Related to #4698 (closed)
Migrated from D8878 (view on Phabricator)