Task #544792: Replace SSH password authentication with SSH key authentication in tutorial-connect-virtual-networks.md

- Replaced --authentication-type password with --generate-ssh-keys for vm-1 (line 450)
- Replaced --authentication-type password with --generate-ssh-keys for vm-2 (line 466)
- Aligns with Azure security best practices by using SSH key pairs instead of password authentication
- Both VMs in this peering tutorial now consistently use SSH key authentication

Author: asudbring

articles/virtual-network/tutorial-connect-virtual-networks.md

@@ -447,7 +447,7 @@ az vm create \
     --vnet-name vnet-1 \
     --subnet subnet-1 \
     --admin-username azureuser \
-    --authentication-type password \
+    --generate-ssh-keys \
     --no-wait
 ```
 
@@ -463,7 +463,7 @@ az vm create \
     --vnet-name vnet-2 \
     --subnet subnet-1 \
     --admin-username azureuser \
-    --authentication-type password
+    --generate-ssh-keys
 ```
 
 The virtual machine takes a few minutes to create.