fix: stop modal appearing in steps (#43728)

* fix: stop showing completion modal on steps

* feat: submit steps with ctrl+enter

* fix: handle ctrl+enter when not focussing editor

* fix: reset tests when user types

* refactor: pass showCompletionModal as an option

Otherwise we have to write executeChallenge(true) which does not mean
what you might reasonably expect.

* fix: always executeChallenge when not on step

* fix: update frontend project show

* fix: handle missing payload

* refactor: isProjectStep -> hasEditableRegion

* refactor: more renaming

* fix: make meta.json control multifile editor use

* fix: update the challengeSchema correctly

* Update client/src/templates/Challenges/classic/editor.tsx

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* fix: remove logging

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

client/src/redux/prop-types.ts

@@ -223,6 +223,7 @@ export type ChallengeNodeType = {
   title: string;
   translationPending: boolean;
   url: string;
+  usesMultifileEditor: boolean;
   videoId: string;
   videoLocaleIds?: VideoLocaleIds;
   bilibiliIds?: BilibiliIds;
@@ -436,6 +437,7 @@ export type ChallengeFile = {
   ext: ExtTypes;
   name: string;
   editableRegionBoundaries: number[];
+  usesMultifileEditor: boolean;
   path: string;
   error: null | string;
   head: string;