"display title" option for view blocks does not work

Not sure we can easily hide the option, I don't think we have the control over the block configuration form without lots of kungfu. Maybe the most pragmatic way would be to simply only send the "title" attribute if the display option is checked.

Added MR. I made the attribute be an empty string instead of NULL, so it's explicit. a NULL attribute would end unset and a possible default value be applied, so with the empty string it should be more clear.

Also extended test-coverage and refactored the test case a bit.

Code looks good, needs testing.

Discussed with usernamee that we do another final test round after merge, so moving on! Thanks for the review!