chore: RuboCop lint Style/MethodMissingSuper

[Insti]

Description

Fix for Rubocop lint Style/MethodMissingSuper
This is part of the RuboCop Quest: #854

Additional Notes

Adds unit test coverage for the Faraday#method_missing method.

[iMacTia]

Thanks for helping us out on the last efforts for this quest 😃!

[Insti]

The assignment to the mock connection

Faraday.default_connection = mock_connection

is persisting throughout the tests.

If the random number generator is unlucky the following error occurs:

       #<Double "Connection"> was originally created in one example but has leaked into another example and can no longer be used. rspec-mocks' doubles are designed to only last for one example, and you need to create a new one in each example you wish to use it for.

I'm working on a fix for this.