Chore: Actions updates and cleanup (#8377)

## Summary

...

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8377-WIP-Chore-Actions-updates-and-cleanup-2f66d73d3650818483a8dffa32a6f245)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>

.github/workflows/pr-size-report.yaml

@@ -33,24 +33,13 @@ jobs:
         github.event_name == 'workflow_dispatch'
       )
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v4.1.0
-        with:
-          version: 10
-
-      - name: Install Node.js
-        uses: actions/setup-node@v5
-        with:
-          node-version: '24.x'
-          cache: pnpm
-
-      - name: Install dependencies
-        run: pnpm install
+      - name: Setup frontend
+        uses: ./.github/actions/setup-frontend
 
       - name: Download size data
-        uses: dawidd6/action-download-artifact@v11
+        uses: dawidd6/action-download-artifact@0bd50d53a6d7fb5cb921e607957e9cc12b4ce392 # v12
         with:
           name: size-data
           run_id: ${{ github.event_name == 'workflow_dispatch' && inputs.run_id || github.event.workflow_run.id }}
@@ -75,7 +64,7 @@ jobs:
           fi
 
       - name: Download previous size data
-        uses: dawidd6/action-download-artifact@v11
+        uses: dawidd6/action-download-artifact@0bd50d53a6d7fb5cb921e607957e9cc12b4ce392 # v12
         with:
           branch: ${{ steps.pr-base.outputs.content }}
           workflow: ci-size-data.yaml
@@ -89,12 +78,12 @@ jobs:
 
       - name: Read size report
         id: size-report
-        uses: juliangruber/read-file-action@v1
+        uses: juliangruber/read-file-action@b549046febe0fe86f8cb4f93c24e284433f9ab58 # v1.1.7
         with:
           path: ./size-report.md
 
       - name: Create or update PR comment
-        uses: actions-cool/maintain-one-comment@v3
+        uses: actions-cool/maintain-one-comment@4b2dbf086015f892dcb5e8c1106f5fccd6c1476b # v3.2.0
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           number: ${{ steps.pr-number.outputs.content }}