Update RobustToolbox to 0.96.6.0 (#15232)

diff --git a/RobustToolbox b/RobustToolbox
index 93dca22ee5c182fed5e4385432e68dc1ae173d12..40c8a3ccf78bd3f9b8f9554242e3bf373c968f89 160000 (submodule)
--- a/RobustToolbox
+++ b/RobustToolbox
@@ -1 +1 @@
-Subproject commit 93dca22ee5c182fed5e4385432e68dc1ae173d12
+Subproject commit 40c8a3ccf78bd3f9b8f9554242e3bf373c968f89