R1:ddcdd6eaf24b

Fix "Undefined offset: 1" exception in Diviner when @task value in PHPDoc is a single word

Summary:
The PHPDoc in https://we.phorge.it/source/phorge/browse/master/src/infrastructure/storage/lisk/LiskMigrationIterator.php$14 defines `* @task storage`.
That means the value of `$task` in the DivinerAtomController class is the single string `storage` and there is no whitespace to `explode` on and there is no second key in the array to set as `$title`.
Thus only call `explode` when `$task` contains a…