Automate manual tests of the `pack` command

## Is Your Feature Request Related To A Problem? Please describe.

There are a few remaining manual tests that we go through for each release. Where possible, these should be extracted from Confluence and automated in the Pester test suite.

## Describe The Solution. Why is it needed?

Machines can do things more reliably and faster than humans. This will reduce the amount of human work needed for a release and allow a tighter loop between committing changes and finding regressions.

## Additional Context.

* This issue is intended to tag the mentioned command tests against.
* These issues are being created without comparing the manual tests with the existing automated tests. It is entirely possible that some or all of them will be closed with no commits as we assess the automated testing coverage.
* These issues are also expected to be long lived and potentially span multiple milestones as we add tests. Where possible all tests should avoid changing the Chocolatey CLI product, and if a test needs a change to allow for this testing a separate issue should be created
* An example of such a tests was adding options to install a `packages.config`, the Pester tests needed to know the configuration at point of install so a debug message was added.

## Related Issues

- List Issue #2837
- Install Issue #2838
- Pin Issue #2839
- Outdated Issue #2840
- Upgrade Issue #2841
- Uninstall Issue #2842
- Pack Issue #2843
- Apikey Issue #2844
- Export Issue #2845

Start by locating the Pester tests for the `pack` command and comparing their coverage with the remaining manual tests in Confluence. Automate applicable cases without changing the Chocolatey CLI; if a product change is required, record it as a separate issue.

Written by the indexing model from the issue text.