[D8 EOL] Remove project_analysis job (Drupal 8 to 9 mass compatibility checks) once Drupal 8 releases are marked unsupported

Problem/Motivation

Once #3248794: [D8 EOL] Mark Drupal 8 only contrib releases unsupported and notify maintainers → happens, the project_analysis job at https://dispatcher.drupalci.org/job/project_analysis/ will filter those incompatible releases out as well (as it does now) and so it will appear like all contributed projects are Drupal 9 compatible. In other words, this job will become obsolete I think.

Steps to reproduce

Proposed resolution

Discontinue the job.

Remaining tasks

User interface changes

API changes

Data model changes