[github-actions] remove use of Glitch from size check (#11684)

.github/workflows/size.yml

@@ -57,14 +57,7 @@ jobs:
     - name: Run
       env:
         OT_BASE_BRANCH: "${{ github.base_ref }}"
-        SIZE_REPORT_URL: "https://openthread-size-report.glitch.me/size-report/1354027"
         GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
       run: |
-        export PATH=$PATH:$HOME/.local/bin
-        if [ ${{ github.event_name }} == pull_request ]; then
-          curl -s --retry 5 "${SIZE_REPORT_URL}/bash" >size-report
-          chmod a+x size-report
-          export OT_SIZE_REPORTER=./size-report
-        fi
         ./script/check-size
         cat /tmp/ot-size-report/report_pr >> $GITHUB_STEP_SUMMARY