GridContainer V-Separation still shows for nodes that are hidden

[CactiChameleon9]

Godot version

v3.5.2.stable.official [170ba33]

System information

Linux, Ryzen 5 4500U, Integrated graphics, GLES2, GLES3

Issue description

The Vertical Separation for a Grid Container is still shown per node even if that node is hidden - meaning space is taken up when it shouldn't be.

See a screenshot below of an (extreme) example:

Steps to reproduce

1. New Scene
2. Control (UI) root node
3. Add a GridContainer
4. Make the GridContainer fill the control (Layout -> Full Rect)
5. Add a ColorRect as a child of the GridContainer
6. Set the ColorRect to expand Horizontally and Vertically in Size Flags
7. Duplicate the ColorRect (CTRL+D) a few times
8. Make the last one hidden and duplicate it more times

You should now see vertical space being taken up by hidden nodes

Minimal reproduction project

GridContainer BugReport.zip

[akien-mga]

Fixed by #76833.