fix: silence powershell progress clixml on windows remotes (#5282)

PowerShell serializes progress records such as module auto-loading's
"Preparing modules for first use." to the stderr CLIXML stream when stderr is
redirected under `-EncodedCommand`, and Herdr forwards that stderr during
interactive remote setup. Set `$ProgressPreference = 'SilentlyContinue'` in the
shared Windows PowerShell preamble so `machine add` and `--remote` no longer
print raw CLIXML records.

refs #4639

(cherry picked from commit 8a20d0b7b5)

src/remote/attach.rs

@@ -537,8 +537,12 @@ fn posix_remote_output_command(command: &str) -> String {
 }
 
 fn windows_powershell_script_command(script: &str) -> String {
+    // `$ProgressPreference = 'SilentlyContinue'` stops PowerShell from
+    // serializing progress records (for example module auto-loading's
+    // "Preparing modules for first use.") into the stderr CLIXML stream that
+    // Herdr forwards to the terminal.
     let script = format!(
-        "[Console]::Out.WriteLine(); [Console]::Out.WriteLine('{REMOTE_OUTPUT_READY_MARKER}'); [Console]::Out.Flush(); {script}"
+        "[Console]::Out.WriteLine(); [Console]::Out.WriteLine('{REMOTE_OUTPUT_READY_MARKER}'); [Console]::Out.Flush(); $ProgressPreference = 'SilentlyContinue'; {script}"
     );
     let utf16 = script
         .encode_utf16()
@@ -4729,7 +4733,7 @@ mod tests {
         ];
 
         let preamble = format!(
-            "[Console]::Out.WriteLine(); [Console]::Out.WriteLine('{REMOTE_OUTPUT_READY_MARKER}'); [Console]::Out.Flush(); "
+            "[Console]::Out.WriteLine(); [Console]::Out.WriteLine('{REMOTE_OUTPUT_READY_MARKER}'); [Console]::Out.Flush(); $ProgressPreference = 'SilentlyContinue'; "
         );
         for (label, command, expected) in commands {
             let script = decode_windows_command(&command);
@@ -4740,6 +4744,21 @@ mod tests {
         }
     }
 
+    #[test]
+    fn windows_remote_commands_suppress_powershell_progress_records() {
+        // PowerShell serializes progress records (such as module auto-loading's
+        // "Preparing modules for first use.") to the stderr CLIXML stream when
+        // stderr is redirected under `-EncodedCommand`. Herdr forwards that
+        // stderr, so the shared preamble must silence progress.
+        let script = decode_windows_command(&windows_powershell_script_command("exit 0"));
+        let preference = "$ProgressPreference = 'SilentlyContinue'; ";
+        assert!(script.contains(preference), "{script}");
+        assert!(
+            script.find(preference).unwrap() < script.find("exit 0").unwrap(),
+            "{script}"
+        );
+    }
+
     #[test]
     fn windows_install_commands_copy_zip_and_return_concrete_path() {
         assert_eq!(