Fix "Queue places per user" and "Queue places per group" defaults not being applied when creating a new activity

[mi-dave]

In Site administration > Plugins > Grouptool > Default instance settings, I have both of these filled in with non-zero values (1 and 5, respectively).

However, when I go to Add an activity or resource > Grouptool, the "limit" checkboxes next to both of these fields are unticked. Despite that, the correct values are displayed in the disabled input fields:

I tracked the cause down to mod_grouptool_mod_form::data_preprocessing(). At first glance, this code looks like it should tick both boxes:

        if (array_key_exists('users_queues_limit', $defaultvalues) && ($defaultvalues['users_queues_limit'] > 0)) {
            $defaultvalues['limit_users_queues'] = 1;
        } else {
            $defaultvalues['limit_users_queues'] = 0;
        }
        if (array_key_exists('groups_queues_limit', $defaultvalues) && ($defaultvalues['groups_queues_limit'] > 0)) {
            $defaultvalues['limit_groups_queues'] = 1;
        } else {
            $defaultvalues['limit_groups_queues'] = 0;
        }

However, it doesn't work for newly created activities because $defaultvalues only contains a subset of the fields at this point, not all of the defaults set in the admin area, so it is always set to 0 for new activities. I have changed it to this:

        if (array_key_exists('users_queues_limit', $defaultvalues)) {
            $defaultvalues['limit_users_queues'] = $defaultvalues['users_queues_limit'] > 0 ? 1 : 0;
        }
        if (array_key_exists('groups_queues_limit', $defaultvalues)) {
            $defaultvalues['limit_groups_queues'] = $defaultvalues['groups_queues_limit'] > 0 ? 1 : 0;
        }

So it only overrides the defaults set in mod_grouptool_mod_form::definition() when a different value is provided - i.e. when editing an existing activity.