Linkage across vertices when Shift-Deleting multiple vertices

When using Shift + Delete on multiple vertices of a path, the position of one vertex can become linked to the handle of a different vertex.

## Steps to reproduce

1. With a blank document, create an ellipse
2. Enable the path tool, and select the right and bottom vertices
3. Press Shift + Delete
4. Separate out the subpaths and observe that moving the right vertex of the smaller subpath changes the direction of the right vertex from the larger subpath

## Video

https://github.com/user-attachments/assets/5d29e193-b274-4360-b7f9-459fba61a83d

## Other details

- Observed on latest and stable web versions
- Seems to apply for any number of nodes highlighted before pressing Shift + Delete, above 1 (however only one node/handle pair has this connection)
- Moving the affected handle directly stops this from happening

Reproduce the issue in the web version using the path tool, an ellipse, and Shift + Delete on multiple vertices. Then trace the path-tool handling for multi-vertex deletion and subpath separation. Done means deleting multiple vertices no longer links one vertex position to another vertex's handle, including when moving the affected vertex or handle.

Written by the indexing model from the issue text.