Fix bug when `$ChocolateyBuildOutput` is null or empty string

[johlju]

Pull Request

Pull Request (PR) description

After a few hours debugging in DscResource.DocGenerator I found that it was this bug that cause the other variables not to be set to correct values, or no mocks was hit as I was expecting. 🙂 Now off to holiday celebration. 🎄

Fixed

• Now the tasks work when using Set-SamplerTaskVariable with tasks that do not have the parameter ChocolateyBuildOutput.

Task list

• [x] The PR represents a single logical change. i.e. Cosmetic updates should go in different PRs.
• [x] Added an entry under the Unreleased section of in the CHANGELOG.md as per format.
• [ ] Local clean build passes without issue or fail tests (build.ps1 -ResolveDependency).
• [ ] Documentation added/updated in README.md.
• [ ] Comment-based help added/updated.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [ ] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9158f6d) 81% compared to head (3ac37bf) 81%. Report is 1 commits behind head on main.

Additional details and impacted files

[](https://app.codecov.io/gh/gaelcolas/Sampler/pull/454?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gael) ```diff @@ Coverage Diff @@ ## main #454 +/- ## =================================== Coverage 81% 81% =================================== Files 44 44 Lines 2326 2328 +2 =================================== + Hits 1902 1904 +2 Misses 424 424 ``` | [Files](https://app.codecov.io/gh/gaelcolas/Sampler/pull/454?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gael) | Coverage Δ | | |---|---|---| | [Sampler/scripts/Set-SamplerTaskVariable.ps1](https://app.codecov.io/gh/gaelcolas/Sampler/pull/454?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gael#diff-U2FtcGxlci9zY3JpcHRzL1NldC1TYW1wbGVyVGFza1ZhcmlhYmxlLnBzMQ==) | `91% <100%> (+<1%)` | :arrow_up: |

[johlju]

Merging this so I can continue working in DscResource.DocGenerator.