MDL-74470 quiz: fix typos & small bug from MDL-74255.

I think that, because how PHP works, the MDL-74255 bug (lack
of explode) generally does not break anything, which is why
no tests failed. Still. Good to fix.

mod/quiz/classes/question/bank/qbank_helper.php

@@ -19,7 +19,6 @@ namespace mod_quiz\question\bank;
 use core_question\local\bank\question_version_status;
 use core_question\local\bank\random_question_loader;
 use qubaid_condition;
-use quiz_attempt;
 
 defined('MOODLE_INTERNAL') || die();
 
@@ -130,7 +129,7 @@ class qbank_helper {
 
              -- This way of getting the latest version for each slot is a bit more complicated
              -- than we would like, but the simpler SQL did not work in Oracle 11.2.
-             -- (It did work find in Oracle 19.x, so once we have updated our min supported
+             -- (It did work fine in Oracle 19.x, so once we have updated our min supported
              -- version we could consider digging the old code out of git history from
              -- just before the commit that added this comment.
              -- For relevant question_bank_entries, this gets the latest non-draft slot number.
@@ -202,17 +201,14 @@ class qbank_helper {
     /**
      * Get this list of random selection tag ids from one of the slots returned by get_question_structure.
      *
-     * @param \stdClass $slotdata one of the array elements returend by get_question_structure.
+     * @param \stdClass $slotdata one of the array elements returned by get_question_structure.
      * @return array list of tag ids.
      */
     public static function get_tag_ids_for_slot(\stdClass $slotdata): array {
-        if (empty($slot->randomtags)) {
-            return [];
-        }
-
         $tagids = [];
-        foreach ($slotdata->randomtags as $tag) {
-            $tagids[] = $tag->id;
+        foreach ($slotdata->randomtags as $taginfo) {
+            [$id] = explode(',', $taginfo, 2);
+            $tagids[] = $id;
         }
         return $tagids;
     }