The import already worked without category, but triggered a warning.
Tests were extended to always work with category, except in new test
case.
All tests were extended to check for empty logs in the end.
The import now checks whether category should be imported and ignores
further processing if not configured.
Relates: #9542
TYPO3 scheduler tasks always have a value for console commands.
Region uid will be an empty string if omitted within scheduler task.
We reflect that in our tests and adapt code to not break.
Furthermore tests call only with strings, as that's what TYPO3 does.
