Ajax enabled page updates changes grouped field IDs with added unwanted string [#3279951]

Problem/Motivation

A grouped field with a set id will have it's ID changed with an added random character string on the end when using ajax enabled page updates such as pagination.

Steps to reproduce

1. Install & Enable Field Group
2. Create a view that displays a enough content to paginate
3. Enable pagination on the view
4. Enable ajax on the view to prevent page refresh when using pagination
5. Create a set of fields nested within a parent field group (we used fieldset but this seems to occur with all)
6. Apply an id to the parent group
7. Apply css styles to the fields within the parent id (not 100% needed to see the bug but how we discovered the issue)
8. Look at your page source code, observe the correct id tag that you applied
9. Press any page number / next / last / etc on the pagination
10. Look at the page's source code again, specifically the id for the group of fields

Observed Result
The group's id has been modified, the id now has an added string of random characters attached, i.e. " id="example" " becomes " id="example-12ewr434rt" "

On our end, we were seeing that our CSS styling was breaking when we would use the pagination