Fix MBart failing test
Fixes the failing test by adjusting the expected sentence. The sentence turns from
```
[...] will only worsen the violence and misery of millions.
```
to
```
[...] only make violence and misery worse for millions of people.
```

which seems grammatically correct still. @patrickvonplaten please let me know if you think this is a real issue or not.
Thanks for fixing this test - this was actually failing since a long time and no-one fixed it