[backport core/1.36] Fix reactivity washing in refreshNodeSlots (#8018)

Backport of #7802 to `core/1.36`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8018-backport-core-1-36-Fix-reactivity-washing-in-refreshNodeSlots-2e76d73d365081ef9188c6baf21e7c1d)
by [Unito](https://www.unito.io)

Co-authored-by: AustinMroz <austin@comfy.org>
Co-authored-by: Alexander Brown <drjkl@comfy.org>

tests-ui/tests/composables/graph/useGraphNodeManager.test.ts

@@ -0,0 +1,49 @@
+import { setActivePinia } from 'pinia'
+import { createTestingPinia } from '@pinia/testing'
+import { describe, expect, it, vi } from 'vitest'
+import { nextTick, watch } from 'vue'
+
+import { useGraphNodeManager } from '@/composables/graph/useGraphNodeManager'
+import { LGraph, LGraphNode } from '@/lib/litegraph/src/litegraph'
+import { NodeSlotType } from '@/lib/litegraph/src/types/globalEnums'
+
+setActivePinia(createTestingPinia())
+
+function createTestGraph() {
+  const graph = new LGraph()
+  const node = new LGraphNode('test')
+  node.addInput('input', 'INT')
+  node.addWidget('number', 'testnum', 2, () => undefined, {})
+  graph.add(node)
+
+  const { vueNodeData } = useGraphNodeManager(graph)
+  const onReactivityUpdate = vi.fn()
+  watch(vueNodeData, onReactivityUpdate)
+
+  return [node, graph, onReactivityUpdate] as const
+}
+
+describe('Node Reactivity', () => {
+  it('should trigger on callback', async () => {
+    const [node, , onReactivityUpdate] = createTestGraph()
+
+    node.widgets![0].callback!(2)
+    await nextTick()
+    expect(onReactivityUpdate).toHaveBeenCalledTimes(1)
+  })
+
+  it('should remain reactive after a connection is made', async () => {
+    const [node, graph, onReactivityUpdate] = createTestGraph()
+
+    graph.trigger('node:slot-links:changed', {
+      nodeId: '1',
+      slotType: NodeSlotType.INPUT
+    })
+    await nextTick()
+    onReactivityUpdate.mockClear()
+
+    node.widgets![0].callback!(2)
+    await nextTick()
+    expect(onReactivityUpdate).toHaveBeenCalledTimes(1)
+  })
+})