Fix inconsistency when serializing objects to JSON between Windows PowerShell and PowerShell Core

[adamdriscoll]

This works on Windows PowerShell but not PowerShell Core

Start-UDDashboard -AutoReload -Wait -Dashboard (
    New-UDDashboard -Title "Example title" -Content {#-Pages $pages
        New-UdTable -Title "Server Information" -Headers @('header1','header2') -Endpoint {
            @{
                'Computer Name'         = 'test1'
                'Operating System'      = 'test2'
                'Total Disk Space (C:)' = 'test3'
                'Free Disk Space (C:)'  = 'test4'
            }.GetEnumerator() | Out-UDTableData -Properties @("Name", "Value")
        }
    }
)