Telematic Plugin: Available topic response return null value for topics field when there is no available topic

[dan-du-car]

Summary

Available topic response return null value for topics field when there is no available topic. This cause issue with requester when it parses the response assuming the topics field is always an array.

Version

4.3.0 (Current)

Expected Behavior

Available topic response should return empty array if there is no topic.

Actual Behavior

Available topic response return null if there is no topic.

Steps to Reproduce the Actual Behavior

1. Run v2xhub
2. Run telematic tool
3. enable telematic plugin
4. Monitor the error output from the telematic server terminal

Related Work

#569