Add support for group names with commas or whitespace in Default Space Permissions

Issue Summary

It's not possible to add a group whose name contains a comma to the Global Site configuration for space permissions (Default Space Permissions)

This page can be found in the UI by navigating from Site Configuration ->Security -> Space permissions

or going to [sitename]/wiki/admin/permissions/viewdefaultspacepermissions.action 

Steps to Reproduce

As a user with Org Admin and Confluence Product Admin privileges:

1. Create a group whose name contains a comma or whitespace.
2. Go to default space permissions [sitename]/wiki/admin/permissions/viewdefaultspacepermissions.action 
3. Type the name of the group which contains a comma or whitespace on its name.
4. When the auto-complete returns it, click on it to select it.
5. Click the Add button

For groups with whitespaces, the group will not be displayed on the picker.

Expected Results

The group is added to the list of groups with permissions on this space.

Actual Results

Two error messages are displayed saying no groups were found. For groups with whitespaces, the group is not displayed.

Notes

• Confluence "believes" there are at least 2 groups trying to be added and each group is separated by commas, when in fact there is only one group trying to be added, only this group has a comma in its name.
• Bug fix should still support adding multiple groups at one time

Workaround

• Add a counter-slash (escape character) before the comma or change the group name and remove the comma.
• For groups with whitespace, delete and re-create the group as group rename is not supported.