docs(storybook): Fix storybook build (#13869)

Remove reference to removed plugin in storybook .babelrc file

.storybook/.babelrc

@@ -7,7 +7,6 @@
     "react-hot-loader/babel",
     "@babel/plugin-syntax-dynamic-import",
     "@babel/plugin-proposal-object-rest-spread",
-    "@babel/plugin-proposal-optional-chaining",
     "@babel/plugin-transform-runtime",
     ["@babel/plugin-proposal-decorators", {"legacy": true}],
     ["@babel/plugin-proposal-class-properties", {"loose": true}]