fixes #6719 / BZ 1079953 - Content Notices - fix deletion and list by org

This commit addresses 2 issues w/ the content notices page:
1. list only the notices associated with the current org
2. update so that clicking 'Delete All' will render the confirmation dialog
Merge pull request #4469 from bbuckingham/issue-6719

fixes #6719 / BZ 1079953 - Content Notices - fix deletion and list by org