[terra-functional-testing] Handle Jenkins setting to disable selenium docker service

[benbcai]

Story

Description

As a maintainer of terra-functional-testing, I want to read the env variable set by Jenkins that indicated the selenium grid is not used for testing

Motivation

So that I know whether or not there is a need to spin up the local selenium docker server to run the tests.

Definition of Done

We'll know we're done when terra-functional-testing can handle this configuration similar to terra-toolkit-boneyard.

Additional Details

When the useSeleniumGrid option in Jenkinsfile is set to false to indicate not to use the selenium grid for testing, we need a new env variable that terra-functional-testing can read to determine to disable the selenium docker service.