This post function will only work in Company-managed/Classic projects.
You can use the Clear Field Value post function to clear the checklist when the issue is transitioned:
Ensure the Save checklist data ot Jira custom fields global setting is enabled.
Navigate to Project Settings > Workflows
Click the pencil icon to edit the workflow.
Select Diagram mode and click on the transition where you want to add the post function.
Click on Post Functions.
Click Add post function.
Select the Clear Field Value post function and click Add.
Select the Checklist Text field and click Add.
Click Publish draft to save the changes.
Test the post function by transitioning an issue to the indicated status. The checklist will be removed.