[Storage] Update live test command for storage packages

[HarshaNalluru]

@bsiegel

In #2047 - 128c033,

is updated to

---

Description

• Nightly tests for storage-packages failed because build:test command wasn't executed.
• This PR attempts to fix the nightly test runs by updating the "unit-browser" command to include "build:test".
• [Storage] Rollup for tests in storage #2297 involves rollup for the tests in storage-packages, I will be updating the "scripts" section in the package.json to stay more consistent with the current package.json of servicebus/eventhubs(either in the same PR or in a follow-up PR).

[bsiegel]

This is fine for now - I am refactoring how the test commands are split out in a PR right now though, and once we have that landed it will fix this problem.

[bsiegel]

👍✨Ship It✨