Update gitlab-advanced-sast-cpp demo projects to use new SAST component/template

Problem to solve

We should provide some examples to showcase the usage of GitLab Advanced SAST CPP in real-world C++ projects.

The demo MRs in clangsa-sast: add demo projects using different... (#556428 - closed) • Hua Yan • 18.5 • On track are still using the old SAST component.

They should be updated once the following are merged:

• gitlab-advanced-sast-cpp: add to SAST CI/CD com... (#534737 - closed) • Hua Yan • 18.6 • Needs attention
• clangsa-sast: add to SAST CI/CD template (#533894 - closed) • Hua Yan • 18.6.

Proposal

• Update demo MRs in clangsa-sast: add demo projects using different... (#556428 - closed) • Hua Yan • 18.5 • On track to use the new SAST component/template.
• Create MRs in https://gitlab.com/gitlab-org/security-products/demos/experiments/cpp-advanced-sast/highway to use demonstrate the usage of the new SAST component/template.
• Verify pipelines run successfully with the updated setup.