[services] Blob - Fix reading data from S3

Summary:
Depends on D3651

Raised in https://phabricator.ashoat.com/D3470#97072

We want to fix reading the S3 object so it doesn't cut the stream on \n

Test Plan:

cd services
yarn test-blob-service

Reviewers: palys-swm, varun, geekbrother, jimpo

Reviewed By: palys-swm

Subscribers: ashoat, palys-swm, Adrian, atul, benschac, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3594