chore(deps): update dependency @edx/frontend-platform to v8.4.0 (#487)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -35,7 +35,7 @@
   "devDependencies": {
     "@edx/brand": "npm:@edx/elm-theme@^1.8.2",
     "@edx/browserslist-config": "^1.1.1",
-    "@edx/frontend-platform": "8.3.9",
+    "@edx/frontend-platform": "8.4.0",
     "@edx/reactifex": "2.2.0",
     "@openedx/frontend-build": "14.6.0",
     "@testing-library/jest-dom": "^5.16.4",