[BUG FIX] [MER-4135] Cannot export some projects (#5330)

* prep 29.2

* [BUG FIX] [MER-4124] broken internal page links

Co-authored-by: Anders Weinstein <[email protected]>

* [BUG FIX] [MER-4126] Fix targeted retake one question at a time

* [BUG FIX] [MER-4118] Improve Student Assessment Submit Terms

* [BUG FIX] [MER-4120] One at a time setting can prevent submissions

* [BUG FIX] [MER-4123] Fix high progress low proficiency filter (#5325)

* [MER-4123] Fix filter for only pages

* [MER-4123] Adds test

* [BUG FIX] [MER-4123] Fix high progress low proficiency filter

* [BUG FIX] [MER-3507] Require instructor login when accessing course section information as account admin

* [BUG FIX] [MER-4127] Fix Learning Objectives Proficiency Distribution Hover Boundary (#5328)

Fixed boundary miscalculation of Proficiency Distribution tooltip and increased stacking context for proper visibility.

See: https://eliterate.atlassian.net/browse/MER-4127

* [BUG FIX] [MER-4011] Real chem course section creation loads indefinitely

* consider children: nil case

---------

Co-authored-by: Darren Siegel <[email protected]>
Co-authored-by: Anders Weinstein <[email protected]>
Co-authored-by: Anders Weinstein <[email protected]>
Co-authored-by: Santiago Simoncelli <[email protected]>
Co-authored-by: Gastón Abellá <[email protected]>
Co-authored-by: Martin Manelli <[email protected]>

lib/oli/interop/export.ex

@@ -440,7 +440,7 @@ defmodule Oli.Interop.Export do
           Map.put(
             revision,
             :children,
-            section_resource.children
+            (Map.get(section_resource, :children) || [])
             |> Enum.map(fn id -> Map.get(resources_by_section_resources, id) end)
           )
         )