test: mark sporadically failing unit tests as flaky

[reubenmiller]

Proposed changes

Mark the following unit tests as flaky:

• bridge_reconnects_successfully_after_cloud_connection_interrupted - similar to ci: run tests using cargo-nextest #3027
• uploaded_file_can_be_downloaded_from_the_api

The failed run was seen in the following CI runs:

• uploaded_file_can_be_downloaded_from_the_api
  • https://github.com/thin-edge/thin-edge.io/actions/runs/10180472337
  • https://github.com/thin-edge/thin-edge.io/actions/runs/10181924590
• uploaded_file_can_be_downloaded_from_the_api
  • https://github.com/thin-edge/thin-edge.io/actions/runs/10181924590/job/28163263896

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

• flaky unittest: bridge_reconnects_successfully_after_local_connection_interrupted #3021
• flaky unittest: file_transfer_server::http_rest::tests::uploaded_file_can_be_downloaded_from_the_api #3030

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
486	0	2	486	100	1h26m18.383366s