ci: remove redundant Pack step (#1115)

## 📜 Description

Remove redundant `Pack` step.

## 💡 Motivation and Context

It looks like I added this step for debugging purposes and forgot to
remove it.

There is no sense to keep it, because `scripts/size.js` already uses
`npm pack --json` command so there is no reason to run the command
twice.

## 📢 Changelog

<!-- High level overview of important changes -->
<!-- For example: fixed status bar manipulation; added new types
declarations; -->
<!-- If your changes don't affect one of platform/language below - then
remove this platform/language -->

### CI

- remove `Pack` command from CI size-diff job.

## 🤔 How Has This Been Tested?

Tested manually via this PR.

## 📸 Screenshots (if appropriate):

<img width="965" height="622" alt="image"
src="https://github.com/user-attachments/assets/0fad211c-b58b-458d-8f2b-6b39ef2652fb"
/>

## 📝 Checklist

- [x] CI successfully passed
- [x] I added new mocks and corresponding unit-tests if library API was
changed

Author: kirillzyusko

.github/workflows/size-diff-collect.yml

@@ -37,9 +37,6 @@ jobs:
       - name: Install dependencies
         run: yarn install --frozen-lockfile
 
-      - name: Pack
-        run: npm pack --json
-
       - name: Calculate size of package (current)
         id: new-size
         run: echo "NEW_SIZE=$(node scripts/size.js)" >> "$GITHUB_OUTPUT"