Replace deprecated ::set-output with $GITHUB_OUTPUT (#737)

## Summary

- Replace deprecated `::set-output` workflow command with the
recommended `>> $GITHUB_OUTPUT` syntax in
`.github/workflows/integration-tests.yml`
- The `::set-output` command has been deprecated by GitHub and is
vulnerable to log injection attacks ([GitHub
changelog](https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/))

## Test plan

- [x] Verify the `check-token` job in `integration-tests.yml` correctly
sets the `has_token` output using the new syntax
- [x] Confirm downstream jobs that depend on
`steps.set-token-status.outputs.has_token` continue to work

NO_CHANGELOG=true

This pull request was AI-assisted by Isaac.

Signed-off-by: Hector Castejon Diaz <hector.castejon@databricks.com>

Author: hectorcast-db

.github/workflows/integration-tests.yml

@@ -23,10 +23,10 @@ jobs:
         run: |
           if [ -z "${{ secrets.DECO_WORKFLOW_TRIGGER_APP_ID }}" ] || [ -z "${{ secrets.DECO_TEST_APPROVAL_APP_ID }}" ]; then
               echo "Required secrets are missing. User has no access to secrets."
-              echo "::set-output name=has_token::false"
+              echo "has_token=false" >> $GITHUB_OUTPUT
           else
               echo "All required secrets are set. User has access to secrets."
-              echo "::set-output name=has_token::true"
+              echo "has_token=true" >> $GITHUB_OUTPUT
           fi
 
   trigger-tests: