change average load test duration to 2 hours

[mmiermans]

References

JIRA: DISCO-TODO

Description

PR Review Checklist

Put an x in the boxes that apply

• [ ] This PR conforms to the Contribution Guidelines
• [ ] The PR title starts with the JIRA issue reference, format [DISCO-####], and has the same title (if applicable)
• [ ] [load test: (abort|warn)] keywords are applied (if applicable)
• [ ] Documentation has been updated (if applicable)
• [ ] Functional and performance test coverage has been expanded and maintained (if applicable)