Remove IPN reference to _relatedObjects, deprecate property

[eileenmcnaughton]

Overview

Removes a line of cruft, adds deprecation

Before

No longer used property copied from one contribution to another

$contribution->_relatedObjects = $objects['contribution']->_relatedObjects;

After

Copy removed, comments updated to clarify that it is no longer used in completeOrder

Technical Details

Comments

[civibot]

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