Added handling for responseType 'LOAD_CANCELLED'

[cweitkamp]

• Added handling for responseType 'LOAD_CANCELLED'

Prevents warnings like these:

2020-05-07 17:00:02.993 [WARN ] [su.litvak.chromecast.api.v2.Channel ] - Error while handling, caused by com.fasterxml.jackson.databind.exc.InvalidTypeIdException: Could not resolve type id 'LOAD_CANCELLED' as a subtype of [simple type, class su.litvak.chromecast.api.v2.StandardResponse]: known type ids = [CLOSE, DEVICE_ADDED, DEVICE_REMOVED, DEVICE_UPDATED, GET_APP_AVAILABILITY, INVALID_REQUEST, LAUNCH_ERROR, LOAD_FAILED, MEDIA_STATUS, MULTIZONE_STATUS, PING, PONG, RECEIVER_STATUS]
 at [Source: (String)"{"requestId":5001,"responseType":"LOAD_CANCELLED","itemId":1}"; line: 1, column: 34]

Signed-off-by: Christoph Weitkamp github@christophweitkamp.de

[vitalidze]

Thank you for the PR. When do you receive such message?

Also, do you mind if I ask you to write unit-test(s) for this case?

[vitalidze]

I think it should fall under the different if branch, throwing an error saying that the Load was cancelled. However I am not sure about the use case.

[cweitkamp]

When do you receive such message?

This warning has been reported in our community: https://community.openhab.org/t/getting-error-playing-mp3-thru-google-assistant/98420

Also, do you mind if I ask you to write unit-test(s) for this case?

In general I would do it but I am afraid my time is very limited at the moment.