Fix vue node slot position calculation (#7877)

## Summary

Fix slot position for Vue nodes using LiteGraph calculation

Fixes #7446

## Changes
- Updated getInput/OutputPos to call getSlotPosition which handles
positions for both LiteGraph & Vue nodes correctly
- Add regression test

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7877-Fix-vue-node-slot-position-calculation-2e16d73d365081219afef0e4ebfb0620)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/lib/litegraph/src/LGraphNode.ts

@@ -1,8 +1,6 @@
 import { LGraphNodeProperties } from '@/lib/litegraph/src/LGraphNodeProperties'
 import {
-  calculateInputSlotPos,
   calculateInputSlotPosFromSlot,
-  calculateOutputSlotPos,
   getSlotPosition
 } from '@/renderer/core/canvas/litegraph/slotCalculations'
 import type { SlotPositionContext } from '@/renderer/core/canvas/litegraph/slotCalculations'
@@ -3349,7 +3347,7 @@ export class LGraphNode
    * @returns Position of the input slot
    */
   getInputPos(slot: number): Point {
-    return calculateInputSlotPos(this.#getSlotPositionContext(), slot)
+    return getSlotPosition(this, slot, true)
   }
 
   /**
@@ -3369,10 +3367,7 @@ export class LGraphNode
    * @returns Position of the output slot
    */
   getOutputPos(outputSlotIndex: number): Point {
-    return calculateOutputSlotPos(
-      this.#getSlotPositionContext(),
-      outputSlotIndex
-    )
+    return getSlotPosition(this, outputSlotIndex, false)
   }
 
   /**