SqlLogin: Should Be Cluster Aware

Details of the scenario you tried and the problem that is occurring:
When the xSQLServerLogin resource is applied to all of the nodes in a Failover Cluster Instance (FCI), all of the nodes will connect to the instance and ensure the desired state is true even if the node is not currently hosting the instance.

The DSC configuration that is using the resource (as detailed as possible):
When the following configuration is applied to two or more nodes in a FCI.

xSQLServerLogin Add_WindowsUser
{
    Ensure               = 'Present'
    Name                 = 'CONTOSO\WindowsUser'
    LoginType            = 'WindowsUser'
    SQLServer            = 'SQLServer'
    SQLInstanceName      = 'DSC'
    PsDscRunAsCredential = $SysAdminAccount
}

Version of the Operating System, SQL Server and PowerShell the DSC Target Node is running:
Any

What module (SqlServer or SQLPS) and which version of the module the DSC Target Node is running:
Any

Version of the DSC module you're using, or 'dev' if you're using current dev branch:
Any

No files or tests are named; start at the xSQLServerLogin resource and reproduce the configuration across multiple FCI nodes. Done means the resource behaves correctly when applied to both the hosting and non-hosting nodes, with the desired login state maintained on the SQL instance.