[examples] Fix duplicate port allocations in C++ SwerveBot/SwerveDrivePoseEstimator/RomiReference (#3773)

- Remove duplicate motor port (2) from C++ SwerveBot/SwerveDrivePoseEstimator

Java has the correct motor ports.

- Fix duplicate port allocation in C++ RomiReference by correcting if/else check

Java logic was already correct, and confirms this change.

wpilibcExamples/src/main/cpp/examples/RomiReference/cpp/subsystems/OnBoardIO.cpp

@@ -17,6 +17,7 @@ OnBoardIO::OnBoardIO(OnBoardIO::ChannelMode dio1, OnBoardIO::ChannelMode dio2) {
   }
   if (dio2 == ChannelMode::INPUT) {
     m_buttonC = std::make_unique<frc::DigitalInput>(2);
+  } else {
     m_redLed = std::make_unique<frc::DigitalOutput>(2);
   }
 }