Don't add babel plugins now added by upstream again in babel.config.js

debian/patches/0740-use-packaged-modules.patch

@@ -2,7 +2,6 @@ Use debian packaged node modules when available
  - Exclude packaged modules from transpiling
  - Remove webpack-bundle-analyzer
  - Resolve .json files
- - Add more plugins to babel.config.js
  - Add mkdirp 1.0 and loader-utils 2.0 to ensure compatibility for packaged
    modules (See #976310)
  - Use link protocol for modules with permission issues (which has a bin: entry
@@ -221,7 +220,7 @@ Use debian packaged node modules when available
      "worker-loader": "^2.0.0",
 --- a/babel.config.js
 +++ b/babel.config.js
-@@ -14,9 +14,12 @@
+@@ -14,6 +14,7 @@
  // include stage 3 proposals
  const plugins = [
    '@babel/plugin-syntax-import-meta',
@@ -229,11 +228,6 @@ Use debian packaged node modules when available
    '@babel/plugin-proposal-class-properties',
    '@babel/plugin-proposal-json-strings',
    '@babel/plugin-proposal-private-methods',
-+  '@babel/plugin-proposal-optional-chaining',
-+  '@babel/plugin-proposal-nullish-coalescing-operator',
-   // See: https://gitlab.com/gitlab-org/gitlab/-/issues/229146
-   '@babel/plugin-transform-arrow-functions',
-   // See: https://gitlab.com/gitlab-org/gitlab/-/issues/336216
 --- a/app/assets/javascripts/pdf/index.vue
 +++ b/app/assets/javascripts/pdf/index.vue
 @@ -1,6 +1,6 @@