429 Error received when fetching a spreadsheet

[benlk]

When fetching a spreadsheet from Google via the API, the API sometimes returns a 429 error. This is because the API request rate has exceeded the rate allowed under the free API.

When the 429 error returns, the app does nothing; it remains in the spinner mode and does not provide any message to the user. In the browser console, an error message is output. I don't have a copy of that message at this time.

This plugin should:

• catch 429 responses and provide a helpful message suggesting that they enable billing on their account: https://developers.google.com/sheets/api/limits
• allow the user to provide an API key to use when making the request, rather than using the free API