In the web app Group Settings page, show a warning when pre-mod is turned on or off

[mkdir-washington-edu]

The problem
At this time, on the Group Settings page for any Private, Restricted, or Open group, you can change the:

• Group name
• Group description
• Group type (Private, Restricted, Open)
• Moderation type (pre-mod on or off)

When you go to change the group type you get a warning message. The reason for this is because this change will affect the annotation visibility for all annotations in the group, and is a significant change to how the group behaves.

Similarly, changing the Pre-mod status in a group also impacts how the group behaves, and should have a similar warning popup forcing the group Owner to confirm they want to make this change.

Potential Solution
Show a warning popup (specific language TBD) when pre-mod is turned on or off, similar to how we show a warning when group type is changed.