Remove all Babel plugins that are included in @babel/preset-env

[MAILPOET-4485]

mailpoet/.babelrc

@@ -5,9 +5,7 @@
     "@babel/preset-env"
   ],
   "plugins": [
-    "@babel/plugin-proposal-nullish-coalescing-operator",
     "babel-plugin-typescript-to-proptypes",
-    "@babel/plugin-proposal-class-properties",
     [
       "@babel/plugin-transform-runtime",
       {
@@ -15,9 +13,6 @@
         "corejs": 3
       }
     ],
-    "@babel/plugin-syntax-dynamic-import",
-    "@babel/plugin-syntax-import-meta",
-    "@babel/plugin-proposal-json-strings",
     [
       "@babel/plugin-proposal-decorators",
       {
@@ -25,8 +20,6 @@
       }
     ],
     "@babel/plugin-proposal-function-sent",
-    "@babel/plugin-proposal-export-namespace-from",
-    "@babel/plugin-proposal-numeric-separator",
     "@babel/plugin-proposal-throw-expressions"
   ]
 }