Prompt for group messages settings on install

[bryonadams]

Checklist

• [X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• [X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• [X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• [X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• [X] This issue contains only one feature request.
• [X] I have read and understood the contribution guidelines.
• [ ] I optionally donated to support the Fossify mission.

Feature description

Upon install, Fossify Messages should prompt the user to select a group message setting.

Why do you want this feature?

Group messages do not actually send as group messages (MMS) by default. This is expected behavior with the current implementation.

If you are migrating to this app from another, the current implementation can lead to confusion when resuming a group text as it causes the thread to split into multiple individual conversations.

See https://github.com/FossifyOrg/Messages/issues/50

Additional information

No response