PG: Handle locks without relations like transactionid or virtualxid locks

[bonnefoa]

What does this PR do?

Include virtualxid and transactionid locks with the pg_locks metrics.

Motivation

In postgres, a transaction can wait for another transaction to end by trying to acquire a sharelock on the target transactionid's lock. We currently exclude those due to the join on relname/schema/db as they have null values.

This PR convert pg_locks to a dynamic query and handles locks with null relname/schema/db.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[github-actions]

⚠️ Major version bump
The changelog type changed or removed was used in this Pull Request, so the next release will bump major version. Please make sure this is a breaking change, or use the fixed or added type instead.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.26%. Comparing base (87e8c9e) to head (7d665ff).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.