fix(test): add -Confirm:\$false to New-PveTemplate call in integration tests

ConfirmImpact.High causes an interactive prompt in CI without
-Confirm:\$false, leading to a null reference error.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/PSProxmoxVE.Tests/Integration/Integration.Tests.ps1

@@ -608,7 +608,7 @@ Describe 'Integration Tests' -Tag 'Integration' {
                 Stop-PveVm -Node $script:Node -VmId $script:LinuxVmId -Wait | Out-Null
             }
 
-            { New-PveTemplate -Node $script:Node -VmId $script:LinuxVmId -ErrorAction Stop } |
+            { New-PveTemplate -Node $script:Node -VmId $script:LinuxVmId -Confirm:$false -ErrorAction Stop } |
                 Should -Not -Throw
 
             # Verify it appears as a template