Avoid to switch the control mode in setReference of the RobotControlHelper

[Giulio Romualdi]

Currently, the RobotControlHelper::setReference switches the control mode of the joints if they are not in the expected configuration. This may lead to errors and RPC calls in the main control loop. After discussing with @S-Dafarra, we decided that it's better to remove this feature.

Warning

Once the PR (that needs to be opened) is merged, several existing code instances will stop working.

cc @mebbaid @isorrentino @S-Dafarra @evelyd @rob-mau

[Giulio Romualdi]

Associated PR: #833