fix: inner groups being moved double when moving outer group (in vue mode) (#7447)

## Summary

Fixes issue when dragging a group that had inner groups when in vue
mode.

When dragging the outer group in Vue mode:

1. getAllNestedItems(selected) returns ALL items: outer group + inner
groups + nodes
2. moveChildNodesInGroupVueMode loops through all items
3. For outer group G1: calls G1.move(delta, true) then
moveGroupChildren(G1, ...)
4. moveGroupChildren calls G2.move(delta) (no skipChildren) - this moves
G2 AND G2's children!
5. Then the loop reaches G2: calls G2.move(delta, true) - moves G2 again
6. Plus moveGroupChildren(G2, ...) processes G2's children again

This PR fixes it by adding `skipChildren=true` to the `move` call.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7447-fix-inner-groups-being-moved-double-when-moving-outer-group-in-vue-mode-2c86d73d365081ce97abec682f2a8518)
by [Unito](https://www.unito.io)

browser_tests/tests/vueNodes/groups/groups.spec.ts

@@ -32,4 +32,42 @@ test.describe('Vue Node Groups', () => {
       'vue-groups-fit-to-contents.png'
     )
   })
+
+  test('should move nested groups together when dragging outer group', async ({
+    comfyPage
+  }) => {
+    await comfyPage.loadWorkflow('groups/nested-groups-1-inner-node')
+
+    // Get initial positions with null guards
+    const outerInitial = await comfyPage.getGroupPosition('Outer Group')
+    const innerInitial = await comfyPage.getGroupPosition('Inner Group')
+
+    const initialOffsetX = innerInitial.x - outerInitial.x
+    const initialOffsetY = innerInitial.y - outerInitial.y
+
+    // Drag the outer group
+    const dragDelta = { x: 100, y: 80 }
+    await comfyPage.dragGroup({
+      name: 'Outer Group',
+      deltaX: dragDelta.x,
+      deltaY: dragDelta.y
+    })
+
+    // Use retrying assertion to wait for positions to update
+    await expect(async () => {
+      const outerFinal = await comfyPage.getGroupPosition('Outer Group')
+      const innerFinal = await comfyPage.getGroupPosition('Inner Group')
+
+      const finalOffsetX = innerFinal.x - outerFinal.x
+      const finalOffsetY = innerFinal.y - outerFinal.y
+
+      // Both groups should have moved
+      expect(outerFinal.x).not.toBe(outerInitial.x)
+      expect(innerFinal.x).not.toBe(innerInitial.x)
+
+      // The relative offset should be maintained (inner group moved with outer)
+      expect(finalOffsetX).toBeCloseTo(initialOffsetX, 0)
+      expect(finalOffsetY).toBeCloseTo(initialOffsetY, 0)
+    }).toPass({ timeout: 5000 })
+  })
 })