Fix access_token expired after 1 hour for Go To plugins

[kuzmany]

Please be sure you are submitting this against the staging branch.

Q	A
Bug fix?
New feature?
Automated tests included?
Related user documentation PR URL
Related developer documentation PR URL
Issues addressed (#s or URLs)
BC breaks?
Deprecations?

Description:

2.15.2 add new Adapt GoTo plugin for oauth2 authentication #7380
But according to the documentation https://goto-developer.logmeininc.com/how-use-refresh-tokens access_token expire every one hour.
This PR try identify If access_token is invalid and then try refresh it (docs above)

Steps to reproduce the bug:

1. Setup GOTO plugin (webinar for example)
2. Authorize, and try use it one hour later. If you are on dev enviroment, you should see error in logs

Steps to test this PR:

1. Load up this PR
2. Repeat all steps. You access token should refresh after one hour

[johbuch]

hi zdeno, I created a new app in gotowebinar, then set the plugin but when I want to push contact to webinar through a form, I can't because my webinar does not appear

I should have a webinar displayed

[kuzmany]

It's new issue?
Or it happend after upgrade?
Could you share with me goto credentials?

[johbuch]

@kuzmany we patched this PR on my instance, I could set and authorised the plugin, but then webinars don't display.
i wrote you on slack

[kuzmany]

@johbuch last commit fixed it.

[Enc3phale]

Tested and it works! Thanks!