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Description
Describe the bug
When the OnFleet API returns an error response they don't always send a 'cause' key in the response which causes the package to throw an exception
To Reproduce
Just try to 'get' a task with an ID that is not on OnFleet(deleted task)
$this->client->tasks->get('example-id')
Expected behavior
Check if the cause exists before trying to set it here
Screenshots

Additional context
N/A