Bump immutable from 5.1.2 to 5.1.5 (#14475)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -45,7 +45,7 @@
     "draft-js-import-element": "https://github.com/swissspidy/draft-js-import-element",
     "draft-js-import-html": "^1.4.1",
     "draftjs-filters": "^3.0.1",
-    "immutable": "^5.1.2",
+    "immutable": "^5.1.5",
     "prop-types": "^15.7.2"
   },
   "devDependencies": {