Previously, we were drawing the context path in the header of the spreadsheet.
However, that had some problems:
* When using a viewer that's somewhere deep in a node group, the viewer path
wouldn't fit.
* Standard editor menus didn't fit in. Also we wanted to add spreadsheet
specific operators that should be in a new menu.
* Couldn't fit more useful data for the context path (like the inspection index
for repeat zones).
This patch solves this by moving the entire context path to the left side bar.
This frees up the header for menus.
The new context panel information is added at the top of the side bar because
then there is a proper hierarchy: `Object > Evaluation State > Viewer Path
(optional) > Instance Selection > Domain Selection`
This patch also adds information about the current inspection index for for-each
and repeat zones. They are not editable yet, but that can be implemented
separately as it might require a few more changes for everything to update
correctly.
The new Viewer Path panel is only displayed when actually showing viewer data.
Pull Request: https://projects.blender.org/blender/blender/pulls/138477
9ac3e44ce6