Avoid linking the same issues

[mtodor]

This PR should fix errors where junit2jira will try to link an issue with itself.

An example: https://github.com/stackrox/stackrox/actions/runs/11819146919/job/32928382775?pr=13326

time="2024-11-13T14:49:43Z" level=info msg="Found 3 failed tests"
time="2024-11-13T14:49:44Z" level=info msg="Found issue. Creating a comment..." ID=ROX-22816 summary="github.com/stackrox/rox/pkg/grpc / Test_APIServerSuite FAILED"
time="2024-11-13T14:49:45Z" level=info msg="Found issue. Creating a comment..." ID=ROX-26980 summary="runtime.MemStats /  FAILED"
time="2024-11-13T14:49:46Z" level=info msg="Found issue. Creating a comment..." ID=ROX-26980 summary="runtime.MemStats /  FAILED"
time="2024-11-13T14:49:46Z" level=fatal msg="could not link issues: 1 error occurred:\n\t* You cannot link an issue to itself.: request failed. Please analyze the request body for more details. Status code: 400\n\n"
Error: Process completed with exit code 1.