[8.x] Allow strings to be passed to the report function

[freekmurze]

Right now, if you want to report something without your code throwing an exception, you have to manually create an exception and pass that to report.

$exception = new \Exception('Something weird occurred, that I want to report, but no exception was thrown'); 

report($exception);

With the change in this PR, that can be simplified, you can just pass a string to report.

report('something weird occurred');

I didn't find any tests for the report function, so I didn't add any. I will gladly add tests if you point where they should be added.