NaNs not handled correctly when in an array

[JayHerpin]

I've seen that there is explicit handling for NaN's in the json messages, but this seems not to be extended to NaNs within arrays.

• Library Version: 1.3.2-1jammy.20240213.165624
• ROS Version: Iron
• Platform / OS: Ubuntu 22.04

Steps To Reproduce

Run command:

ros2 topic pub /fix sensor_msgs/msg/NavSatFix "{latitude : .nan, longitude : .nan, altitude : .nan, status : {status : -1, service : 1}, position_covariance : [.nan, .nan, .nan, .nan, .nan, .nan, .nan, .nan, .nan]}"

to publish problematic data

Subscribe to topic /fix from nodejs or similar

Expected Behavior All NaN values in the encoded json message should be encoded as :Null

Actual Behavior

As you can see, while the non-array members are encoded correctly, the values within the array are not

[RamiCMT]

This has been causing problems for roslibjs as well.

If I have a serial GPS node publishing data without proper reception, missing values encoded as NaN cause roslibjs' subscriber's JSON.parse() to throw an error.