exclude deleted groups from group_name_is_unique? check
exclude deleted groups from group_name_is_unique? check

Signed-off-by: Graham Ballantyne <41f44c895bdc135de4883e2e29d129fe203bf0d8@sfu.ca>

sfu/canvas_spaces,sfu/canvas-spaces,sfu/canvas-spaces,sfu/canvas_spaces,sfu/canvas-spaces,sfu/canvas_spaces