chore: 🤖 Upgrade addons/core to Ember 4.12.2 (#1965)

* chore: 🤖 Upgrade `addons/core` to Ember 4.12.2

Upgrade `addons/core` to Ember 4.12.2

✅ Closes: ICU-11341

* refactor: 💡 testing updating plugin-proposal-decorators version

Update `@babel/plugin-proposal-decorators` to latest version.

* refactor: 💡 testing legacy plugin-proposa-decorators version

Testin `legacy` version for `plugin-proposal-decorators` plugin

* refactor: 💡 testing plugin-proposal-decorators

Testing `@babel/plugin-proposal-decorators`

* refactor: 💡 Revert @babel/exlint-parser to previous version

Revert `@babel/eslint-parser` to use version 2018 EcmaScript version
until further research is done on latest versions

* Update package.json

put @babel/core back into `devDependencies`

* refactor: 💡 testing linging changes

Pushed ember-tempalate-lint, prettier, and ember template lint plugin
for prettier to latest versions to test why CI builds are not passing.

✅ Closes: https://hashicorp.atlassian.net/browse/ICU-11341

addons/api/package.json

@@ -31,8 +31,8 @@
     "ember-fetch": "^8.1.1"
   },
   "devDependencies": {
-    "@babel/core": "^7.18.5",
-    "@babel/eslint-parser": "^7.21.3",
+    "@babel/core": "^7.21.0",
+    "@babel/eslint-parser": "^7.18.2",
     "@babel/plugin-proposal-decorators": "^7.21.0",
     "@ember/optional-features": "^2.0.0",
     "@ember/string": "^3.0.1",