fix(storage): make storage robust to edge case on region selection

[frgfm]

This PR changes the image used for localstack in dev environment.

We were using localstack/localstack:1.4.0, which is both outdated (2 years ago, not ideal for security) and too big (includes all AWS services, while we only need file storage). The new image is about 100Mb, vs. 750Mb previously

UPDATE: there is almost no documentation for the s3-latest minimal image (https://discuss.localstack.cloud/t/set-up-s3-bucket-using-docker-compose/646/2), so I'll just update localstack image which got smaller with recent releases : 450Mb vs 750Mb on our current image.

(The end-to-end test script ensures the behaviour hasn't changed)

Several difficulties with localstack, adding articles for reference:

• bug: Unable to run localstack localstack/localstack#9963

EDIT: I reverted back to 1.4.0, and fixed the issues that weren't already detected by extending the tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.85%. Comparing base (abce184) to head (21e590e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #407      +/-   ##
==========================================
+ Coverage   84.83%   84.85%   +0.01%     
==========================================
  Files          35       35              
  Lines         996      997       +1     
==========================================
+ Hits          845      846       +1     
  Misses        151      151              

Flag	Coverage Δ
backend	84.36% <100.00%> (+0.01%)	⬆️
client	92.06% <ø> (ø)

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