[SE-4441] Change week numbering in onboarding_and_trial_period_evaluation.md
Description
Jira Ticket: SE-4441
This MR changes the week numbering in Onboarding and Trial Period like so:
- Week 0 -> Week 1
- Week 1 -> Week 2
- Week 2 -> Week 3
- Week 3 -> Week 4
- Week 4 -> Week 5
Edited by Hamza Chandad