[ROS2 Dashing] unnecessary warning at default use_sim_time parameter

[IanTheEngineer]

@artivis - in both the source repo and ros-testing Debians on ROS Dashing, I receive this warning every time I launch the node:

[joy_teleop-2] [WARN] [joy_teleop]: parameter use_sim_time is not a dict

use_sim_time is a standard parameter supplied to every node at launch-time. If unset or set to False, the node should use system time, True to use sim_time.

Regardless of whether this node handles use_sim_time itself, it should handle the param more gracefully than throwing a warning in this codeblock:
https://github.com/ros-teleop/teleop_tools/blob/dashing-devel/joy_teleop/joy_teleop/joy_teleop.py#L75-L95

[artivis]

@bmagyar Wasn't this closed by #38 ?

[bmagyar]

Unfortunately it was caused by #38 , see the commit here adding the dict warning here: 37074a5