Fixes Compare-Object Exception if there are currently no CertificateN…

[ChristophHannappel]

Pull Request (PR) description

Fixes an Issue where the Ressource Get-SPCertificateSettings fails when setting SPCertificateNotificationContact and there are currently none set.

This Pull Request (PR) fixes the following issues

• Fixes #1430

Task list

• [X] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [x] Examples appropriately added/updated.
• [X] 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:

Project coverage is 84%. Comparing base (c8281f1) to head (b310e7d).

Additional details and impacted files

[](https://app.codecov.io/gh/dsccommunity/SharePointDsc/pull/1437?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dsccommunity) ```diff @@ Coverage Diff @@ ## master #1437 +/- ## ====================================== - Coverage 84% 84% -1% ====================================== Files 145 145 Lines 22805 22809 +4 ====================================== + Hits 19234 19236 +2 - Misses 3571 3573 +2 ``` | [Files](https://app.codecov.io/gh/dsccommunity/SharePointDsc/pull/1437?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dsccommunity) | Coverage Δ | | |---|---|---| | [...ertificateSettings/MSFT\_SPCertificateSettings.psm1](https://app.codecov.io/gh/dsccommunity/SharePointDsc/pull/1437?src=pr&el=tree&filepath=SharePointDsc%2FDSCResources%2FMSFT_SPCertificateSettings%2FMSFT_SPCertificateSettings.psm1&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dsccommunity#diff-U2hhcmVQb2ludERzYy9EU0NSZXNvdXJjZXMvTVNGVF9TUENlcnRpZmljYXRlU2V0dGluZ3MvTVNGVF9TUENlcnRpZmljYXRlU2V0dGluZ3MucHNtMQ==) | `100% <100%> (ø)` | | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/dsccommunity/SharePointDsc/pull/1437/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dsccommunity)