chore(react-components): add npm pkg fontobserver-es

This change adds `fontobserver-es` npm module monitor when a webfont is loaded and notify.
Please note that it is different from `fontfaceobserver` module, we
choose `fontobserver-es` because it's an es module.

ref:
- bramstein/fontfaceobserver#118
- https://github.com/dmnsgn/fontfaceobserver

packages/react-components/package.json

@@ -17,6 +17,7 @@
   "dependencies": {
     "@twreporter/core": "^1.4.2-rc.0",
     "@twreporter/redux": "^7.2.2",
+    "fontfaceobserver-es": "^3.3.3",
     "hoist-non-react-statics": "^2.3.1",
     "lodash": "^4.0.0",
     "memoize-one": "^5.0.5",

yarn.lock

@@ -8862,6 +8862,11 @@ follow-redirects@^1.0.0:
   dependencies:
     debug "^3.2.6"
 
+fontfaceobserver-es@^3.3.3:
+  version "3.3.3"
+  resolved "https://registry.yarnpkg.com/fontfaceobserver-es/-/fontfaceobserver-es-3.3.3.tgz#b8fa6b774592c53d4ff98b031f97f15f9bdc4d83"
+  integrity sha512-1EyweL1ryy0koZWk80Kr0UgWq9KhbOl2cD6x1O8BtFu0gNqCWIXK1lVFSUb37DI5FMn1m86I6X7N1JRBy8wVfw==
+
 for-in@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/for-in/-/for-in-1.0.2.tgz#81068d295a8142ec0ac726c6e2200c30fb6d5e80"