Update enable-network-protection.md

Updated the Windows Server info, where Windows Server 2019 was missing in the PoSh cmdlet.  And added that for the downlevel servers, it requires the unified agent for MDE.

Author: YongRhee-MSFT

defender-endpoint/enable-network-protection.md

@@ -84,8 +84,8 @@ To enable network protection, you can use one of the following methods:
 
    | Windows Server version | Commands |
    |---|---|
-   | Windows Server 2022 and later | `set-mpPreference -AllowNetworkProtectionOnWinServer $true` |
-   | Windows Server 2016 <br/>Windows Server 2012 R2 | `set-MpPreference -AllowNetworkProtectionDownLevel $true` <br/> `set-MpPreference -AllowNetworkProtectionOnWinServer $true` |
+   | Windows Server 2019 and later | `set-mpPreference -AllowNetworkProtectionOnWinServer $true` |
+   | Windows Server 2016 <br/>Windows Server 2012 R2 with the [unified agent for Microsoft Defender for Endpoint](https://learn.microsoft.com/defender-endpoint/enable-network-protection) | `set-MpPreference -AllowNetworkProtectionDownLevel $true` <br/> `set-MpPreference -AllowNetworkProtectionOnWinServer $true` |
 
 4. (This step is optional.) To set network protection to audit mode, use the following cmdlet: