ci: Modify changelog generation and output

.github/workflows/release.yml

@@ -221,13 +221,11 @@ jobs:
         run: |
           release_version="$(cat ./artifacts/release-version)"
           echo "RELEASE_VERSION=$release_version" >> $GITHUB_ENV
-          changelog_body="$(cat ./artifacts/changelog.md)"
-          echo "changelog_body=$(cat artifacts/changelog.md)" >> $GITHUB_ENV
 
       - name: Validate release environment variables
         run: |
           echo "Release version: ${{ env.RELEASE_VERSION }}"
-          echo "Changelog body: ${{ env.changelog_body }}"
+          echo "Changelog body: $(cat artifacts/changelog.md)"
 
       - name: Get bumped Cargo files (Act)
         if: env.ACT == 'true'