feat(rules): support Labels with SectionName in ResolveTargetRef function

[lobkovilya]

Motivation

It's a valid use case to use both Labels and SectionName in to[].targetRef.

Implementation information

• refactored ResolveTargetRef method to avoid duplicating logic
• added unit tests

[github-actions]

Reviewer Checklist

🔍 Each of these sections need to be checked by the reviewer of the PR 🔍:
If something doesn't apply please check the box and add a justification if the reason is non obvious.

• Is the PR title satisfactory? Is this part of a larger feature and should be grouped using > Changelog?
• PR description is clear and complete. It Links to relevant issue as well as docs and UI issues
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as an image registry)
• IPv6 is taken into account (.e.g: no string concatenation of host port)
• Tests (Unit test, E2E tests, manual test on universal and k8s)
  • Don't forget ci/ labels to run additional/fewer tests
• Does this contain a change that needs to be notified to users? In this case, UPGRADE.md should be updated.
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label)

[slonka]

Just Qs

[slonka]

this seems unrelated 🤔

[lobkovilya]

The function parseService was copied from here outbound_converter.go. When a port is not specified, i.e. backend_kuma-demo_svc it returned reserved port value 49151.

I don't really know why we need this reserved value in outbound_converter.go, but in resolvedtargetref.go I didn't want to introduce extra handling of special values especially when value 0 works perfectly fine for this case. Otherwise, I'd have to add here something like

- if q.port == 0 && q.sectionName == "" {
+ if (q.port == 0 || q.port == mesh_proto.TCPPortReserved) && q.sectionName == "" {

[slonka]

should we somehow document that it was copied? or maybe we should make it DRY?