Only display kinematics warning if no groups have an IK solver

[Abishalini]

Description

This warning appeared every time I launched MoveIt even though I had kinematics information assigned for each planning group.

[WARN] [1719602728.013530753] [waypoint_manager_node.moveit.ros.robot_model_loader]: No kinematics plugins defined. Fill and load kinematics.yaml!

I am removing the check to see if the robot model has JointModelGroups (the groups defined in the SRDF) as it does not pertain to the warning.

Closed this PR since this was not the root cause of the problem.

Checklist

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