[services] Blob - Fix unit tests

Summary:
Depends on D4216

Fixing bucket names in blob service unit tests. The assumption is that we're always going to run the unit tests in dev mode. So we can skip using some alternative bucket name like commapp-test

Test Plan:

cd services
yarn run-unit-tests blob

Reviewers: palys-swm

Reviewed By: palys-swm

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

Differential Revision: https://phab.comm.dev/D4251