Maya Scene exports do not default to including nodes that not children of members

[BigRoy]

Changelog Description

On Maya scene exports only include the relevant history for the selected nodes downstream and upstream and not upstream, and also their downstream descendant children.

Additional info

Note: This may affect maya scene exports, camera rig exports and layout exports. However, I do feel this is a way more sensible default behavior on exports with construction history enabled.

With this change, if you have a hierarchy like:

grp/
    obj1
    obj2

And obj1 is inside the instance then after this PR obj2 is not included.
Before this PR all other descendents from upstream groups would be included, regardless of whether they were "inputs" to the obj1.

After this PR, if obj2 is an input connection to obj1 (e.g. there are active constraints driving obj1 or some other connections driving it) then obj2 will still be included.

As such, only objects actively contributing to members of the instance will still be included in the output.

Testing notes:

1. Recreate the aforementioned hierarchy from additional info.
2. Publish obj1 - it should not include obj2
3. Now make a connection from obj2 to obj1 (e.g. translate connection)
4. Now obj2 should also be included in obj2.
5. Now disconnect the connection, and key obj1 transforms.
6. The keys should be exported along just fine.

[LiborBatek]

All of those aformentioned cases worked for me and it produces correct publish.

LGTM

[moonyuet]

Code looks good for me.
(Just a line of small tweak)

[BigRoy]

Fingers crossed this won't break expectancy for anyone else. :) 🤞