Add source_xid attribute to the ErrorTracking in CreateVulnerabilityService class

Proposal

Add source_xid attribute to ErrorTracking in CreateVulnerabilityService class.

The following discussion from !136138 (merged) should be addressed:

• @brytannia started a discussion: (+3 comments)

  question: In case of the error, we will have similar error tracked in CreateVulnerabilityService, but it won't have source_xid param. What are purposes of each messages in this case?

The source_xid parameter is helpful to have so that the origin of the advisory is known. Combined with the advisory_xid attribute, you can track down where an advisory came from easily.

Implementation plan

• Add source_xid to attr_reader and initialize source_xid in the advisory data object of the VulnerabilityScanning::Advisory class.
• Within the AdvisoryScanner class, include source_xid in the creation of the Gitlab::VulnerabilityScanning::Advisory object in the vulnerability_scanning_advisory method. This involves creating VulnerabilityScanning::Advisory from a data object that contains source_xid.
• Update the factories and test cases accordingly.
• When using the CreateVulnerabilityService, ensure that source_xid is passed to the ::Gitlab::ErrorTracking.track_exception methods.