fix(tools): Update createStepFile function in new curriculum helper script (#41693)

* feat: add parseMDSync to parser

* fix: update createStepFile function

Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

tools/challenge-helper-scripts/create-step-between.js

@@ -1,7 +1,7 @@
 const {
   reorderSteps,
   createStepFile,
-  getChallengeSeed,
+  getChallengeSeeds,
   padWithLeadingZeros,
   getExistingStepNums,
   getProjectPath,
@@ -35,13 +35,13 @@ if (!allStepsExist(existingSteps, [start, end])) {
   throw 'Step not created. At least one of the steps specified does not exist.';
 }
 
-const challengeSeed = getChallengeSeed(
+const challengeSeeds = getChallengeSeeds(
   `${projectPath}part-${padWithLeadingZeros(start)}.md`
 );
 createStepFile({
   stepNum: start,
   projectPath,
-  challengeSeed,
+  challengeSeeds,
   stepBetween: true
 });
 console.log(`Sucessfully added step between step #${start} and step #${end}`);