fix: keep native-command stderr from aborting schtasks/reg.exe on WinPS 5.1

Under Windows PowerShell 5.1 with $ErrorActionPreference = 'Stop', a native
command that writes to stderr (captured via 2>&1) raises a terminating error.
reg.exe writes its success message to stderr and schtasks.exe writes to stderr
for a missing task, so on the 5.1 runtime the payload actually ships to, importing
a .reg file or disabling/removing an absent scheduled task threw instead of
succeeding/warning. pwsh 7 doesn't behave this way, so pwsh-only CI never caught
it. Run each native call under a local 'Continue' preference. Surfaced by the new
Windows PowerShell 5.1 test leg.

Author: jacksyrm

playbook/Executables/AtlasModules/Scripts/Modules/Atlas.Registry/Domain/RegFile.ps1

@@ -18,7 +18,14 @@ function Import-AtlasRegFile {
     }
 
     $regExePath = Join-Path -Path ([Environment]::GetFolderPath('System')) -ChildPath 'reg.exe'
-    $output = & $regExePath import "$Path" 2>&1
+    $previousErrorActionPreference = $ErrorActionPreference
+    $ErrorActionPreference = 'Continue'
+    try {
+        $output = & $regExePath import "$Path" 2>&1
+    }
+    finally {
+        $ErrorActionPreference = $previousErrorActionPreference
+    }
     if ($LASTEXITCODE -ne 0) {
         $details = (@($output) | ForEach-Object { "$_" }) -join ' '
         throw "reg.exe import failed for '$Path' (exit code $LASTEXITCODE): $details"

playbook/Executables/AtlasModules/Scripts/Modules/Atlas.TasksProcs/Domain/ScheduledTasks.ps1

@@ -21,7 +21,14 @@ function Invoke-AtlasScheduledTaskCommand {
         [switch]$IgnoreMissing
     )
 
-    $output = & schtasks.exe @Arguments 2>&1
+    $previousErrorActionPreference = $ErrorActionPreference
+    $ErrorActionPreference = 'Continue'
+    try {
+        $output = & schtasks.exe @Arguments 2>&1
+    }
+    finally {
+        $ErrorActionPreference = $previousErrorActionPreference
+    }
     if ($LASTEXITCODE -eq 1) {
         if (-not $IgnoreMissing) {
             Write-AtlasLog -Level Warning -Message "Scheduled task '$Path' was not found; nothing to $OperationLabel."

playbook/Executables/AtlasModules/Scripts/Modules/Atlas.Tweaks/Domain/Invoke.ps1

@@ -123,16 +123,23 @@ function Invoke-AtlasTweakScheduledTaskEntries {
             # locale-independent existence probe decides which failure this actually is -
             # otherwise access-denied and similar real errors would be logged as a
             # harmless missing task.
-            $null = & schtasks.exe /Query /TN "$taskPath" 2>&1
-            if ($LASTEXITCODE -ne 0) {
-                Write-AtlasLog -Message "Scheduled task '$taskPath' was not found; nothing to $($operation.ToLowerInvariant())." -Level Warning
-                continue
-            }
+            $previousErrorActionPreference = $ErrorActionPreference
+            $ErrorActionPreference = 'Continue'
+            try {
+                $null = & schtasks.exe /Query /TN "$taskPath" 2>&1
+                if ($LASTEXITCODE -ne 0) {
+                    Write-AtlasLog -Message "Scheduled task '$taskPath' was not found; nothing to $($operation.ToLowerInvariant())." -Level Warning
+                    continue
+                }
 
-            $output = & schtasks.exe /Change /TN "$taskPath" $stateArgument 2>&1
-            if ($LASTEXITCODE -ne 0) {
-                $details = (@($output) | ForEach-Object { "$_" }) -join ' '
-                throw "schtasks.exe exited with code $LASTEXITCODE - $details"
+                $output = & schtasks.exe /Change /TN "$taskPath" $stateArgument 2>&1
+                if ($LASTEXITCODE -ne 0) {
+                    $details = (@($output) | ForEach-Object { "$_" }) -join ' '
+                    throw "schtasks.exe exited with code $LASTEXITCODE - $details"
+                }
+            }
+            finally {
+                $ErrorActionPreference = $previousErrorActionPreference
             }
         }
         catch {