Rename qa-staging to e2e-run-staging

What does this MR do?

Part of Rename `qa-staging` Slack channel (gitlab-org/quality/quality-engineering/team-tasks#2807 - closed)

Renames qa-staging Slack channel to e2e-run-staging

Check-list

• Ensure commits include Changelog: trailer
• Verify the change in all affected pipelines.

Post-merge Checklist

• A new release of pipeline-common must be created and published.
• The new release's version must be referenced in the Staging environment project. The version must be updated.