test: workaround supertest ECONNRESET

[alxndrsn]

TODO

• confirm expected ci results (maybe re-run ~5x):
  • should fail: https://github.com/alxndrsn/odk-central-backend/actions/runs/13829942667
  • should pass: https://github.com/alxndrsn/odk-central-backend/actions/runs/13829946244
• revert ci changes
• revert lint changes
• revert blobs changes
• revert encryption test changes

---

Closes #1440

What has been done to verify that this works as intended?

Ran a big matrix of tests, repeatedly: https://github.com/alxndrsn/odk-central-backend/actions?query=branch%3Aeconreset

Why is this the best possible solution? Were any other approaches considered?

• it's simple
• it should clearly report any new errors in express startup & shutdown
• it references the upstream issue, so workaround can be removed at some point

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

It's a test change, so should not affect users.

Does this change require updates to the API documentation? If so, please update docs/api.yaml as part of this PR.

It's a test change, so should not affect API documentation.

Before submitting this PR, please make sure you have:

• run make test and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code from external sources are properly credited in comments or that everything is internally sourced

[alxndrsn]

unrelated

[alxndrsn]

Fixed upstream.