[TECHNICAL-SUPPORT] LPS-31857 Site Pages portlet and Manage Page pop-up allow permission overriding via drag-n-drop

Hey Tamás,

LPS-31857 and LPS-33282 have been created to fix the same issue in navigation, and in Site Pages (and Manage page) portlets.

As we have agreed, I'm checking MANAGE_LAYOUTS permission to enable or disalbe page drag&drop.
I've just modified @zsagia's previous commits according to this requirement.

I'm sending another pull for LPS-33282.

Regards,
Tibor