feat: let users save cert project code to db (#44700)

* feat: let users save cert project code to db

fix: move getChallenges call out of request function so it only runs once

fix: use FlashMessages enum

fix: transform challengeFiles earlier

test: make tribute page use multifile editor

stuff I was playing with - revert this to get it to a working state

refactor: allow undefined editableRegionBoundaries

fix: save history

history is not necessarily ["name.ext"] and using the incorrect history
could cause weird bugs

fix: replace files -> challengeFiles on the client

refactor: DRY out ajax

fix: use file -> challengefile map

refactor: rename ajax types

fix: alphatize flash-messages.ts

revert: tribute page project

fix: remove logs

fix: prettier

fix: cypress

fix: prettier

fix: remove submitComplete action

fix: block UI for new projects

fix: handle code size

* fix: catch undefined files

* fix: don't default to undefined when it's already the default

* fix: only update savedChallenges if applicable

* fix: dehumidify backend + fine tune nearby stuff

* fix: prop-types

* fix: dehumidify sagas

* fix: variable name

* fix: types

* Apply suggestions from code review

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

* fix: typo

* fix: prettier

* fix: props types

* fix: flash messages

* Update client/src/utils/challenge-request-helpers.ts

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

* chore: rename function uniformize -> standardize

* fix: flash message

* fix: add link to forum on flash messages

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>
Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

cypress/integration/learn/responsive-web-design/intro-page.js

@@ -4,6 +4,7 @@ const selectors = {
 
 describe('Certification intro page', () => {
   before(() => {
+    cy.exec('npm run seed');
     cy.clearCookies();
     cy.login();
     cy.visit('/learn/responsive-web-design');