Empty pages parameter displays only the tasks under the current page

[trrenty]

Describe the bug
You can insert a task report macro inside a page and set, using the wiki mode, an empty value for the pages parameter. This will cause it to filter for all the tasks that are under the current page. While this is a neat feature, since we can't set such a value using the wysiwyg editor, we shouldn't support it as it is.

To Reproduce
Steps to reproduce the behavior:

1. Create PageA with the following content {{task reference="/Tasks/Task_0"}}Task from PageA{{/task}}.
2. Create PageA.PageB with the following content:

{{task reference="/Tasks/Task_0"}}Task from PageB{{/task}}

{{task-report pages="" status="InProgress"/}}

3. Observe PageA.PageB

Expected behavior
The task report macro should display both the tasks Task from PageA and Task from PageB.

Actual Behaviour
The task report macro displays only the Task from PageA.

Screenshots
N/A

Environment (please complete the following information):
N/A

Additional context
As a workaround, removing the pages="" will fix the issue.