Make test dependencies conditional so we can enable them when running autopkgtest

--- a/Gemfile
+++ b/Gemfile
@@ -333,7 +333,7 @@
 gem 'webrick', '~> 1.6','>= 1.6.1', require: false
 gem 'prometheus-client-mmap', '~> 0.12.0', require: 'prometheus/client'
 
-group :development, :test do
+if ENV["INCLUDE_TEST_DEPENDS"] == "true"
   gem 'deprecation_toolkit', '~> 1.5', '>= 1.5.1', require: false
   gem 'bullet', '~> 6.1', '>= 6.1.3'
   gem 'pry-byebug'
@@ -371,9 +371,7 @@
   gem 'rblineprof', '~> 0.3.6', platform: :mri, require: false
 
   gem 'test_file_finder', '~> 0.1.3'
-end
 
-group :test do
   gem 'fuubar', '~> 2.2'
   gem 'rspec-retry', '~> 0.6.1'
   gem 'rspec_profiling', '~> 0.0.6'