Feat: support retries in e2e tests in CI

[jpraynaud]

Content

This PR includes support for retrying e2e test runs in case of transient error on the Cardano network of the underlying devnet (which happen because of the custom configuration used for it). This will overall remove the main source of flakiness in the CI runs.

Error handling improvements:

• mithril-test-lab/mithril-end-to-end/src/devnet/runner.rs: Introduced UnrecoverableDevnetError and updated error handling in impl Devnet to use this new error type.

Main execution flow restructuring:

• mithril-test-lab/mithril-end-to-end/src/main.rs: Refactored the main function to use a new AppResult enum for handling different exit codes and added implementation for Termination to map results to exit codes.

Enhancements to GitHub workflows:

• .github/workflows/backward-compatibility.yml: Added retry logic to the E2E tests using nick-fields/retry@v3.
• .github/workflows/ci.yml: Added retry logic to the Test job using nick-fields/retry@v3.

Pre-submit checklist

• Branch
  • Tests are provided (if possible)
  • Crates versions are updated (if relevant)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
• PR
  • No clippy warnings in the CI
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested

Issue(s)

Closes #2123

[github-actions]

Test Results

    4 files  ±0     52 suites  +1   11m 47s ⏱️ -1s
1 416 tests +2  1 416 ✅ +2  0 💤 ±0  0 ❌ ±0 
1 627 runs  +2  1 627 ✅ +2  0 💤 ±0  0 ❌ ±0 

Results for commit d78c7a3. ± Comparison against base commit e38a254.

♻️ This comment has been updated with latest results.