🐛(storybook) add typescript docgen config

A recent update on react-docgen-typescript dependancy broke storybook
build.
This configaration is a workaround until storybook 6.3 releases.

Related issue: storybookjs/storybook#15067

src/frontend/.storybook/main.js

@@ -1,4 +1,11 @@
 module.exports = {
   stories: ['../components/**/*.stories.@(js|jsx|ts|tsx)'],
   addons: ['@storybook/addon-a11y', '@storybook/addon-essentials'],
+
+  // workaround for https://github.com/storybookjs/storybook/issues/15067
+  // storybook 6.3 should fix it
+  typescript: {
+    // also valid 'react-docgen-typescript' | false
+    reactDocgen: 'react-docgen',
+  },
 };