ci: fix semgrep reported run-shell-injection (#1630)

Author: oakrizan

.github/workflows/run-test/action.yml

@@ -43,8 +43,11 @@ runs:
         && (inputs.sauce-username != null && inputs.sauce-username != '')
       shell: bash
       run: |
-        echo "SAUCE_ACCESS_KEY=${{ inputs.sauce-access-key }}" >> $GITHUB_ENV
-        echo "SAUCE_USERNAME=${{ inputs.sauce-username }}"     >> $GITHUB_ENV
+        echo "SAUCE_ACCESS_KEY=$SAUCE_ACCESS_KEY" >> $GITHUB_ENV
+        echo "SAUCE_USERNAME=$SAUCE_USERNAME" >> $GITHUB_ENV
+      env:
+        SAUCE_ACCESS_KEY: ${{ inputs.sauce-access-key }}
+        SAUCE_USERNAME: ${{ inputs.sauce-username }}
     - name: Run tests Elastic Stack ${{ matrix.stack-version }} - ${{ matrix.scope }} - ${{ fromJSON('{"none":"Puppeteer"}')[inputs.mode] || inputs.mode }}
       run: './.ci/scripts/test.sh'
       shell: bash