Fix phantom test failures from tool first-run spinners writing to os.Stdout (#9028)

The tool first-run middleware creates detect/install spinners via
uxlib.NewSpinner without setting Writer, so they default to os.Stdout and
emit cursor escape codes (\033[?25l / \033[?25h) during unit tests. Under
'go test -json' these raw bytes corrupt the event stream, causing phantom
'unknown'/FAIL results on this and adjacent middleware tests.

Route both spinners through m.console.Handles().Stdout, matching the prompts
in the same file. Under MockConsole this handle is io.Discard (no leakage in
tests); in production it is the real stdout, so behavior is unchanged.

Author: JeffreyCA

cli/azd/cmd/middleware/tool_first_run.go

@@ -230,6 +230,7 @@ func (m *ToolFirstRunMiddleware) runFirstRunExperience(ctx context.Context) erro
 	detectSpinner := uxlib.NewSpinner(&uxlib.SpinnerOptions{
 		Text:        "Detecting tools...",
 		ClearOnStop: true,
+		Writer:      m.console.Handles().Stdout,
 	})
 	if err := detectSpinner.Run(ctx, func(ctx context.Context) error {
 		var detectErr error
@@ -416,6 +417,7 @@ func (m *ToolFirstRunMiddleware) offerInstall(
 	installSpinner := uxlib.NewSpinner(&uxlib.SpinnerOptions{
 		Text:        "Installing tools...",
 		ClearOnStop: true,
+		Writer:      m.console.Handles().Stdout,
 	})
 	installErr := installSpinner.Run(ctx, func(ctx context.Context) error {
 		var batchErr error