fix(pages): add canEdit to page deletion permission check


Description: using canEdit allows plugins to override the delete permission check (e.g. groups owners in the group_tools plugin). I did not mark the function pages_can_delete_page in lib/pages as private since it could be used by other plugins.

Fixes #7007

Duplicate of pull requests #7012 and #7645 

It was for this branch. You asked me to change it in #7645 but I had created a pull request against the wrong branch (1.x) so I closed it and opened this one with your code in the first commit