This PR adds tests for actuator initialization, configuration, and
computation for Implicit, IdealPD, and DC motor actuators.

This PR also updates the DCMotor model to clip based on a four quadrant
DC motor model. This will fix improper clipping in the negative power
regions (i.e. positive torque and negative velocity or negative torque
and positive velocity).

NOTE: This PR is dependant on the pytest migration in:
[2034](https://github.com/isaac-sim/IsaacLab/pull/2034)
This PR includes changes made in
[2291](https://github.com/isaac-sim/IsaacLab/pull/2291) and would be an
alternate candidate.

Fixes [#2139](https://github.com/isaac-sim/IsaacLab/issues/2139)

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---------
Signed-off-by: Kelly Guo <kellyg@nvidia.com>
Signed-off-by: James Tigue <166445701+jtigue-bdai@users.noreply.github.com>
Signed-off-by: Kelly Guo <kellyguo123@hotmail.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: Kelly Guo <kellyguo123@hotmail.com>