console: Fix fetching stats if there are no gateways

[PavelJankoski]

Summary

There was an error shown instead of empty table when trying to fetch statistics with empty list.

Changes

Added condition to check, if there are no gateway, don't send request to fetch batch statistics.

Testing

1. Login in the console.
2. Go to /console/gateways.
3. Have an empty slate of not having gateways.
4. An error should not be shown.

Notes for Reviewers

This was fixed in ENT PR

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• The steps/process to test this feature are clearly explained including testing for regressions.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.