fix #1585 Issue when a resizable/movable dialog is disposed shortly after its creation
fix #1585 Issue when a resizable/movable dialog is disposed shortly after its creation

As the aria.utils.dragdrop.Drag and aria.utils.resize.Resize utilities
are loaded asynchronously (only if the dialog configuration requires
those classes), it is possible that the dialog is disposed before those
classes are loaded, so the callback should check it before doing anything
else.

vcarle/ariatemplates,fbasso/ariatemplates,vcarle/ariatemplates,benouat/ariatemplates,divdavem/ariatemplates,ariatemplates/ariatemplates,simonarbuckle/ariatemplates,ymeine/ariatemplates,fbasso/ariatemplates,ariatemplates/ariatemplates,benouat/ariatemplates,ymeine/ariatemplates,divdavem/ariatemplates,divdavem/ariatemplates,benouat/ariatemplates,ariatemplates/ariatemplates,vcarle/ariatemplates,simonarbuckle/ariatemplates,ymeine/ariatemplates,simonarbuckle/ariatemplates,fbasso/ariatemplates