[13.x] Use exception object in JobAttempted event

[bert-w]

The /Illuminate/Queue/Events/JobAttempted event is very useful to track job completions/failures, however in its current form it only passes down an exception that occurred as a bool.

This PR changes this to pass down the complete Throwable $e so we have more data to work with in the event itself.

Since this is a breaking change I targeted 13.x. Existing userland code that listens to this event might need to be updated.