Ability for site admin to view all submitted jobs on Job Dashboard

Requested in https://wordpress.org/support/topic/adding-search-field-to-job_dashboard/

Our project has a single admin that posts ALL jobs. Ideally, they could see EVERY job listing (regardless of who posted it) in their [Job_Dashboard].

I tested to make sure; site admins do not see all submitted jobs on the dashboard.

Start by reproducing the behavior in the Job_Dashboard as a site admin, then trace how submitted jobs are filtered by the posting user. The requested outcome is that a site admin can see every submitted job regardless of who posted it; verify this with listings from multiple users.

Written by the indexing model from the issue text.