Require'ing `test_file_finder` is slow due to `faraday` dependency

Problem

requireing test_file_finder takes ~0.5s on my machine. This slowness mostly due to require 'faraday'.

$ be irb
>> require "benchmark"
=> true
>> Benchmark.realtime { require 'test_file_finder' }
=> 0.5955067549948581
>>

$ be irb
>> require "benchmark"
=> true
>> Benchmark.realtime { require 'faraday' }
=> 0.5750473000007332
>> Benchmark.realtime { require 'test_file_finder' }
=> 0.05927275300200563

Proposed solution

Autoload strategy GitlabMergeRequestRspecFailure to only load faraday when required and thus speed up load time if not.