Check WordPress environment when automatically refreshing token

[n7studios]

Summary

When a call is made with an expired access token, checks the WordPress environment to determine if the WordPress Libraries should automatically attempt to refresh the expired access token.

If the environment is configured in the WordPress configuration file and is not a production site, no automatic attempt to refresh an expired access token will occur.

This is designed to mitigate this reported issue, where the same ConvertKit creator account used on both a staging and production site results in the staging site obtaining the new access token first, resulting in the production site unable to refresh the same expired access token. Whilst each site should receive its own unique access token when first going through the OAuth flow, this doesn't seem to be the case - possibly because of the special redirect URI we use.

Testing

• testRefreshTokenWhenAccessTokenExpiredErrorOnNonProductionSite: Tests that the automatic attempt to refresh an expired access token does not occur when WP_ENVIRONMENT_TYPE is not production. Individual Plugins should also perform their own unit tests with these libraries to confirm the same.

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• Code meets WordPress Coding Standards for PHP, HTML, CSS and JS
• Security and Sanitization requirements have been followed
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)

[noelherrick]

@cainwatson Anything we can do here besides this solution? This seems like odd behavior.

[cainwatson]

@cainwatson Anything we can do here besides this solution? This seems like odd behavior.

Hey! We're aware this is an issue, but I've unfortunately been OOO and other things have taken priority. If this temporarily mitigates the issue, go ahead and release. I'll make sure that when our PM gets back next week this is on his radar.