Users who do not have the create issue permission should not be shown when selecting a default reporter on the Issue Collector

When configuring the Issue Collector form, an admin is allowed to assign any users (except inactive users) as the default reporter. As such, the default reporter can be a user who does not have the create issue permission.

As a result, there would be an error when someone is trying to create a feedback from the issue collector.

The following stacktrace appears on the logs:

2013-03-28 13:43:22,107 http-bio-8600-exec-21 ERROR guest 823x402x1 1hmw0r8 127.0.0.1 /rest/collectors/1.0/template/custom/3873c579 [collector.plugin.rest.TemplateResource] Detected missing fields in collector 'Test Issue Collector' (id: 3873c579, project: DEMO): [pid]