[commands] Deprecate Command.schedule() (#7072)

It's only syntactic sugar over the CommandScheduler's schedule method and creates a footgun because it’s too obvious to try to use in incorrect places.

Co-authored-by: Starlight220 <53231611+Starlight220@users.noreply.github.com>

wpilibcExamples/src/main/cpp/templates/commandbasedskeleton/cpp/Robot.cpp

@@ -22,7 +22,7 @@ void Robot::AutonomousInit() {
   m_autonomousCommand = m_container.GetAutonomousCommand();
 
   if (m_autonomousCommand) {
-    m_autonomousCommand->Schedule();
+    frc2::CommandScheduler::GetInstance().Schedule(m_autonomousCommand.value());
   }
 }