GTL: do not set parent_id directly  from params[:id].
GTL: do not set parent_id directly  from params[:id].

This was introduced in https://github.com/ManageIQ/manageiq-ui-classic/pull/2383

I am failing to find a usecase where the assignment from params[:id]
would be needed so I am removing it.

Fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=1509171

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic