Convert request method to POST to get past 5000 character limit

Here's an attempt at fixing the tests. The main issue was simply not returning the JSON missing the translatedText item with error messages, etc.. I also added looking for the POST data, the request method and cleaned up some assertions. I'm not a phpunit expert, so there may be more to do. Hopefully, this moves the ball forward.

Fix linting issue.

Thanks for improving the tests, didn't test very large characters but seems to work at least as well as before.

Automatically closed - issue fixed for 2 weeks with no activity.

Hello.
All patches can't apply for tmgmt_google 8.x-1.1