PointCloud Display keeps more than just the latest message when decay time is 0

[StefanFabian]

A decay time of 0 should only keep the latest points.
However, as it is currently implemented, if multiple messages are queued at the same time (I am not sure why that happens; my point clouds only come with 10Hz, but I'm still experiencing it), the display will show more than just the last message.

This is caused by the following lines:

rviz/rviz_default_plugins/src/rviz_default_plugins/displays/pointcloud/point_cloud_common.cpp

Lines 422 to 427 in f15a160

	bool PointCloudCommon::cloudInfoIsDecayed(
	CloudInfoPtr cloud_info, float point_decay_time, const rclcpp::Time & now)
	{
	return (now.nanoseconds() - cloud_info->receive_time_.nanoseconds()) / 1000000000.0 >
	point_decay_time;
	}

Changing this to >= fixes the issue and should not make a difference for non-zero decay times in real-world usage since it's a floating point number and the likelihood of them being equal for a non-zero value is close to zero.