Fail rather than emitting a deprecation warning when the value of a `Property` typed task property is changed after the task starts execution. Also include the property display name, if attached, in the 'cannot change the value' error messages.
Add `HasMultipleValue.finalizeValue()` method to allow the value of a collection property to be made final. Attempts to change the property value after this method is called will fail. Use this in the native plugins and remove the internal `LockableCollectionProperty` implementation as it is no longer needed.