Application may see a JavaScript error due to insufficient Observation data

[kolkheang]

The sample application can run into a JavaScript error when the response from the server does not have the appropriate Observation data. The application should ensure that data is valid before accessing the data.

The component object can be nil. Currently the find function is accessing this component object without checking.

https://github.com/cerner/smart-on-fhir-tutorial/blob/gh-pages/example-smart-app/src/js/example-smart-app.js#L92-L93