bundle the package in order to get the size for an entry point

[Feiyang1]

A packages might be split into multiple files in order to share code between entry points. The shared code is extracted to a shared file that all entry points import.
As a result, an entry point file may not include all code and we need to make a bundle to get the actual size of the entry point.

[changeset-bot]

⚠️ No Changeset found

Latest commit: f406c22

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[google-oss-bot]

Size Analysis Report

Affected Products

No changes between base commit (9822e12) and head commit (2d5a660).

Test Logs

• Base (9822e125): https://github.com/firebase/firebase-js-sdk/actions/runs/372843711
• Head (2d5a660d): https://github.com/firebase/firebase-js-sdk/actions/runs/373220637