Create metrics for the SBOM trigger similar to the existing advisory db

Why are we doing this work

As in this discussion &8026 (comment 2006922854), we want to have metrics for sbom trigger on sbom changes similar to the existing one.

Relevant links

Non-functional requirements

• Documentation:
• Feature flag:
• Performance:
• Testing:

Implementation plan

• backend Add a new event category, action and label to be the input of :Gitlab::Tracking
• backend As the CVS on sbom change is pipeline centered, we could provide the pipeline_id, the amount of sbom possibly affected and known affected as input for the event. Start and end times could also be provided.

Verification steps