Change in Follow-up tickets for Side Conversations

Feature Request Summary:

Follow-up tickets for Side Conversations are created on the original group value only, or, in case it no longer exists, the standard group. Currently, the follow-up ticket for Side Conversations is created on the original assignee and group value. 

Description/Use Cases: 

When the original assignee is no longer an agent, no follow-up ticket is created, and the message in the Side Conversation will never be seen, as it is still on the closed ticket. 
If Follow-up tickets for Side Conversations are created on the original group value only, there is a much higher chance it will actually be created. And having a fallback where the current Standard group is selected, in case the original group no longer exist, will ensure a follow-up is always created.

Business impact of limitation or missing feature:

This is critical for our customers, as with the current function, follow-up tickets are sometimes not created and messages are missed. We have a few customers with higher employee turnover, so this is a genuine exposure. Missing a follow-up message from a customer can certainly have a high impact. 

Other necessary information or resources:

None