[DOP-24570] Exclude dataset symlinks with no inputs/outputs

[dolfinus]

Change Summary

Before - dataset symlinks are always included into lineage graph:

After - dataset symlinks are included only of they have some input or output:

This reduces visual noise.

Related issue number

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.90%. Comparing base (a25bcae) to head (1212264).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #189      +/-   ##
===========================================
+ Coverage    91.87%   91.90%   +0.02%     
===========================================
  Files          197      197              
  Lines         4872     4889      +17     
  Branches       338      342       +4     
===========================================
+ Hits          4476     4493      +17     
  Misses         327      327              
  Partials        69       69              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.