MDL-34841 error importing questions with long names.

The problem was with the non-UTF-8-safe way that a question name
was being constructed from the question text.

I have done a proper fix with methods in the base class to
carefully construct a question name that is reasonable, and
which will fit in the database column. Then I have changed all
importers to use the new methods.

I also remembered not to break the lesson in the process.

question/format/learnwise/format.php

@@ -126,10 +126,7 @@ class qformat_learnwise extends qformat_default {
 
         $question = $this->defaultquestion();
         $question->qtype = MULTICHOICE;
-        $question->name = substr($questiontext, 0, 30);
-        if (strlen($questiontext) > 30) {
-            $question->name .= '...';
-        }
+        $question->name = $this->create_default_question_name($questiontext, get_string('questionname', 'question'));
 
         $question->questiontext = $questiontext;
         $question->single = ($type == 'multichoice') ? 1 : 0;