Get-UpdateCatalogDownloadInfo sometimes returns null, which later causes an exception

[mlongwell]

Occasionally, LatestUpdate will sometimes throw an exception.

During Get-LatestServicingStackUpdate.ps1, line 97 throws an exception, stating that $downloadInfo is null. https://github.com/aaronparker/LatestUpdate/blob/50e8c79c760593247ef36574b8ca759a5b779e01/LatestUpdate/Public/Get-LatestServicingStackUpdate.ps1#L97 This variable is supposed to be set on line 94 while calling Get-UpdateCatalogDownloadInfo, but it looks like this function occasionally returns null: https://github.com/aaronparker/LatestUpdate/blob/50e8c79c760593247ef36574b8ca759a5b779e01/LatestUpdate/Public/Get-LatestServicingStackUpdate.ps1#L94