Add additional test function for vscode

[danquack]

Not sure if y'all would want this, but this has made it helpful from my contributions in the AWS provider to test just the one function vs running things on the cli.

If not feel free to just close. I thought about opening an issue, but the code is fairy small its easier just to decline imo

Hashi docs: https://hashicorp.github.io/terraform-provider-aws/debugging/#set-up-launchjson

[github-actions]

changelog detected ✅

[jacobbednarz]

thanks! happy to add it in if others are using it.

[github-actions]

Oops! It looks like no changelog entry is attached to this PR. Please include a release note as described in https://github.com/cloudflare/terraform-provider-cloudflare/blob/master/contributing/changelog-process.md.

Example:

```release-note:TYPE
Release note
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If you do not require a release note to be included and you have permission, please add the workflow/skip-changelog-entry label. Otherwise, a maintainer will add the label or ask you for one when they review the PR.

[github-actions]

This functionality has been released in v4.18.0 of the Terraform Cloudflare Provider.

Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!