Fix integration test: Allow some time for the mocked-monitor process to terminate

otherwise the test will fail on Windows when the cleanup function tries to remove the
executable:

Error Trace:	D:/a/arduino-cli/arduino-cli/internal/integrationtest/environment.go:46
                D:/a/arduino-cli/arduino-cli/internal/integrationtest/environment.go:56
                D:/a/arduino-cli/arduino-cli/internal/integrationtest/environment.go:56
                D:/a/arduino-cli/arduino-cli/internal/integrationtest/environment.go:62
                D:/a/arduino-cli/arduino-cli/internal/integrationtest/daemon/daemon_concurrency_test.go:127
Error:          Received unexpected error:
                remove C:\Users\runneradmin\AppData\Local\Temp\cli2489057723\A\packages\builtin\tools\serial-monitor\0.14.1\serial-monitor.exe: Access is denied.
Test:           TestInitAndMonitorConcurrency

Author: cmaglie

internal/integrationtest/daemon/daemon_concurrency_test.go

@@ -124,4 +124,9 @@ func TestInitAndMonitorConcurrency(t *testing.T) {
 	require.LessOrEqual(t, time.Since(start), 4*time.Second)
 	cancel()
 	monitorCompleted.Wait()
+
+	// Allow some time for the mocked-monitor process to terminate (otherwise the
+	// test will fail on Windows when the cleanup function tries to remove the
+	// executable).
+	time.Sleep(2 * time.Second)
 }