internal/prompt: Confirm: don't wrap stdIn

This was a remnant from when `PromptForConfirmation` accepted a `InStream`;
it was added in [moby@30b8f08], which got left behind when [cli@37ccc00]
updated its signature to accept a plain `io.Reader`.

While updating, also update the comment to provide more context on the reason
we're unconditionally using `os.Stdin` on Windows.

[moby@30b8f08]: moby/moby@30b8f08
[cli@37ccc00]: 37ccc00

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

internal/prompt/prompt.go

@@ -88,8 +88,18 @@ func Confirm(ctx context.Context, in io.Reader, out io.Writer, message string) (
 	_, _ = out.Write([]byte(message))
 
 	// On Windows, force the use of the regular OS stdin stream.
+	//
+	// StdStreams() may wrap stdin with windowsconsole.NewAnsiReader to
+	// emulate VT input on consoles that do not support it natively, but
+	// that wrapper has historically caused interactive prompts to hang
+	// or behave incorrectly.
+	//
+	// See:
+	// - https://github.com/moby/moby/issues/14336
+	// - https://github.com/moby/moby/issues/14210
+	// - https://github.com/moby/moby/pull/17738
 	if runtime.GOOS == "windows" {
-		in = streams.NewIn(os.Stdin)
+		in = os.Stdin
 	}
 
 	result := make(chan bool)