Add presign url get other costs

[Kariamos]

This pull request enhances the API for campaign finance "other costs" by adding presigned S3 URLs to each attachment, improving secure access to files. It updates both the backend logic and the OpenAPI schema, and introduces comprehensive tests to ensure correct behavior.

API and Schema Enhancements:

• Each attachment in the "other costs" API response now includes a presigned_url property, allowing secure, time-limited access to S3 files. [1] [2] [3] [4]

Backend Logic Improvements:

• The getPresignedUrl function now accepts a configurable expiration time (default 20 minutes), and is used to generate presigned URLs for each attachment with a 3-hour expiration in the route handler. [1] [2] [3]

Testing Updates:

• The test suite for the "other costs" endpoint was updated to:
  • Mock the getPresignedUrl function for predictable results.
  • Assert that each attachment includes a presigned_url in the response. [1] [2] [3] [4]
  • Verify that getPresignedUrl is called with the correct parameters for each attachment and the intended expiration time.

[github-actions]

Tests difference:

New Tests

< GET /campaigns/campaignId/finance/otherCosts - Should call getPresignedUrl for each attachment

[coveralls]

coverage: 79.778% (+0.03%) from 79.746%
when pulling d874ec5 on add-presign-url-get-other-costs
into 26d19f4 on UN-2274-other-costs.