Removing UN/PW from IKEv2

The username and password authentication option for IKEv2 for iOS was removed from the MEM admin center about a year ago; cleaning up docs to reflect this change.

Author: tycastMSFT

memdocs/intune/configuration/vpn-settings-ios.md

@@ -208,7 +208,6 @@ These settings apply when you choose **Connection type** > **IKEv2**.
       - **ECDSA384**
       - **ECDSA521**
 
-  - **Username and password** (User authentication only): When users connect to the VPN, they're prompted for their username and password.
   - **Shared secret** (Machine authentication only): Allows you to enter a shared secret to send to the VPN server.
     - **Shared secret**: Enter the shared secret, also known as the pre-shared key (PSK). Be sure the value matches the shared secret configured on the VPN server.