client: fix excessive socket messages listeners
client: fix excessive socket messages listeners

Navigating from general view to group detail
wasn't destroying socket messages listeners
but was adding a new listener each time we were
entering or leaving a group as the
ManageMainController is used by both the general
view and the group detail view.

veo-labs/openveo-manage,veo-labs/openveo-manage,veo-labs/openveo-manage