test: add test to exponential backoff with jitter

[jooola]

Missing test for the jitter code.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #481 +/- ## ======================================= Coverage ? 71.54% ======================================= Files ? 45 Lines ? 3876 Branches ? 0 ======================================= Hits ? 2773 Misses ? 690 Partials ? 413 ```

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