New nodes added in the wrong place

# Reproduction - Create new document - Open node graph - Right click to add new node near the bottom of the node graph view - Select node - Observe it is added **not** in the location of the right click. # Video https://github.com/user-attachments/assets/d56ad06d-f2f9-4265-9dea-0949e7fe49f3 # Code A shifted version of the mouse position is used to spawn the node instead of the proper position. https://github.com/GraphiteEditor/Graphite/blob/2c29d2c40614a0ea51b8be113daba2f7f54c4209/editor/src/messages/portfolio/document/node_graph/node_graph_message_handler.rs#L866-L875 https://github.com/GraphiteEditor/Graphite/blob/2c29d2c40614a0ea51b8be113daba2f7f54c4209/frontend/src/components/views/Graph.svelte#L142