Rename EdgeGateway::Configure integration tests

So that they reflect the classs and subset of functionality that they are
testing. I missed these in 37efc5b7f8a1b88626a5dd976b0f05b727ba10e2.
Merge pull request #66 from alphagov/71524632-rename_configure_integration_tests

[Fixes #71524632] Rename EdgeGateway::Configure integration tests