min_turning_r_ getting param fix (ros-navigation#4510)

* min_turning_r_ getting param fix

Signed-off-by: Ivan Radionov <[email protected]>

* Update nav2_mppi_controller/include/nav2_mppi_controller/motion_models.hpp

Signed-off-by: Steve Macenski <[email protected]>
Signed-off-by: Ivan Radionov <[email protected]>

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Signed-off-by: Ivan Radionov <[email protected]>
Signed-off-by: Steve Macenski <[email protected]>
Co-authored-by: Ivan Radionov <[email protected]>
Co-authored-by: Steve Macenski <[email protected]>