Attempt to make the test suite more stable

[p-schlickmann]

Hey @rosa! How you've been?

Using the CI artifact with Rails logs has been very helpful to diagnose the flakes 🎉.

This PR aims to fix 3 things:

• Increase retention period for CI logs
• Fix flakiness at concurrency_controls_test.rb#L38
• Ensure to stop dispatchers after assertion runs. Those unstopped dispatchers were interfering with lifecycle_hooks_test.rb#L89 assertion sometimes.

[p-schlickmann]

Whoops... Seems like I messed up concurrency_controls_test.rb#L38

Taking a look 😅.

[p-schlickmann]

Seems like I got it right this time @rosa! Can you double check?

I believe that test is asserting "000" will be overwritten by the NonOverlapping jobs. I just increased the time gap between each job to prevent races.

The assertion was failing like this:

--- expected 
+++ actual 
@@ -1 +1 @@ 
- "sAcAsBcBsCcCsDcDsEcEsFcFsGcGsHcHsIcIsJcJsKcK" 
+ "s000c000sAcAsBcBsCcCsDcDsEcEsGcGsHcHsIcIsJcJsKcK"

[rosa]

Looks good! Thank you @p-schlickmann!