replace Button unit tests with snapshot tests

Author: ethanshar

package.json

@@ -90,6 +90,7 @@
     "react-native-keyboard-tracking-view": "^5.6.1",
     "react-native-navigation": "^3.4.0",
     "react-native-reanimated": "^1.7.0",
+    "react-test-renderer": "^16.13.1",
     "shell-utils": "^1.0.10",
     "typescript": "^3.8.3"
   },