Adding Tests for MyLocationScreen and ui.ts

[ptbhatcoder]

✅ I have read the contributing file

Summary

The following changes are made in the pull request in the interest of improving the test coverage and minimising UI regressions

Changelog

• Fixed a type in one of the string keys from PLATEFORM to PLATFORM
• Added the missing snapshot tests for MyLocationScreen
• Refactored the above component to optimise renders
• Adding missing tests for ui.ts

Demo

yarn build; yarn test; yarn lint:fix

[PierreBresson]

Thanks!