Don't automatically reopen resolved tickets on customer reply

When a ticket is marked Resolved, it should remain resolved unless an agent decides it needs to be reopened. A customer replying doesn't automatically mean the original issue is unresolved. They may simply say thank you, ask where the fix was made, or ask how to use the solution. The previous behavior, where only Waiting on Customer tickets automatically returned to In Progress, more accurately reflected the status of the issue. Automatically reopening resolved tickets makes the ticket status less accurate and creates unnecessary work. This behavior should be configurable so each workspace can choose the workflow that best fits its support process.