Scanning Should Complete Successfully Even If There Is Nothing to Scan
### Summary
Some customers want to enable scanning on all projects regardless on if there is anything to scan and then have the analyzer exit with a `0` and complete successfully if there is nothing to scan.
As per https://gitlab.com/gitlab-org/gitlab/-/issues/209747#note_1115905975, DS and SAST analyzers now fail with exit code `0` when a scanning job is triggered (based on `rules:exist`), but the analyzer doesn't support the project; it no longer fails with `3`.
Adding a source code file in those repositories, just for sake of testing, allows the pipeline to completed successfully.
### Steps to reproduce
1. Enable Scanning on project that has nothing to scan.
2. Run pipeline.
3. Pipeline will exit with 0, but will not complete successfully.
### Example Project
https://gitlab.com/dunelm/platform-engineering/tf-ecs-test/-/pipelines/648291156
### What is the current *bug* behavior?
Job does not complete successfully, even though nothing has failed.
### What is the expected *correct* behavior?
Job should complete successfully, where or not there is anything to scan.
### Relevant logs and/or screenshots
https://gitlab.com/dunelm/platform-engineering/tf-ecs-test/-/pipelines/648291156
issue