Add new DAST schema fields to backend for API Fuzzing

Problem to solve

Expose new fields added to the DAST report schema. The new fields are needed to perform the frontend work related to adding API Fuzzing to the security dashboard and MR.

Proposal

Update the backend as needed to expose the new fields for frontend development.

1. Replace test report used by specs with an API Fuzzer report including new fields ee/spec/fixtures/security_reports/master/gl-coverage-fuzzing-report.json
2. Update backend code as needed ee/lib/ci/parsers/security
3. Update tests

Links / references

/cc @sethgitlab @stkerr