Add UT for reconcileVPCResource function

[Karthik-K-N]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes # Related to https://github.com/kubernetes-sigs/cluster-api-provider-ibmcloud/issues/1818

Special notes for your reviewer:

/area provider/ibmcloud

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Release note:

[netlify[bot]]

✅ Deploy Preview for kubernetes-sigs-cluster-api-ibmcloud ready!

Name	Link
🔨 Latest commit	080e3eed606dcda80e77d49d791caf8bf0310eff
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-sigs-cluster-api-ibmcloud/deploys/672c54b91fc0bd00089268a4
😎 Deploy Preview	https://deploy-preview-2031--kubernetes-sigs-cluster-api-ibmcloud.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[Amulyam24]

/retitle Improve UT coverage for IBMPowerVSCluster controller

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Amulyam24, Karthik-K-N, Prajyot-Parab

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• ~~OWNERS~~ [Prajyot-Parab]

Approvers can indicate their approval by writing /approve in a comment Approvers can cancel approval by writing /approve cancel in a comment