Fix ActiveJob tests for Rails 7.2 and 8.0

[olivier-thatch]

Description

This PR fixes the test suite so that the ActiveJob related tests pass with Rails 7.2 and 8.0.

While working on the ActiveJob integration, I noticed that one of the tests was failing with Rails 7.2 and 8.0, specifically this one:

sentry-ruby/sentry-rails/spec/sentry/rails/activejob_spec.rb

Lines 310 to 324 in 1eb011b

	context "when we are using an adapter which has a specific integration" do
	before do
	Sentry.configuration.rails.skippable_job_adapters = ["ActiveJob::QueueAdapters::TestAdapter"]
	end
	after do
	Sentry.configuration.rails.skippable_job_adapters = []
	end
	it "does not trigger sentry and re-raises" do
	expect { FailedJob.perform_now }.to raise_error(FailedJob::TestError)
	expect(transport.events.size).to eq(0)
	end
	end

After investigating, I realized that with Rails >= 7.2, all the test jobs were using ActiveJob::QueueAdapters::AsyncAdapter as their queue adapter instead of ActiveJob::QueueAdapters::TestAdapter. This is likely because of this change that was introduced in Rails 7.2.

The fix is easy enough: we simply need to make sure ActiveJob::TestHelper is included before the test suite runs. After including the helper module, all test jobs correctly use ActiveJob::QueueAdapters::TestAdapter as their queue adapter.

What I don't understand is why this happens locally but not in CI 🤔

#skip-changelog

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.19%. Comparing base (48f45e8) to head (325b3c1).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2487      +/-   ##
==========================================
+ Coverage   98.15%   98.19%   +0.04%     
==========================================
  Files         128      128              
  Lines        4827     4885      +58     
==========================================
+ Hits         4738     4797      +59     
+ Misses         89       88       -1     

Components	Coverage Δ
sentry-ruby	98.59% <ø> (+0.04%)	⬆️
sentry-rails	97.07% <ø> (ø)
sentry-sidekiq	96.96% <ø> (ø)
sentry-resque	92.85% <ø> (ø)
sentry-delayed_job	95.65% <ø> (ø)
sentry-opentelemetry	99.31% <ø> (ø)

see 3 files with indirect coverage changes