[backport 1.25] Implement subgraph unpacking (#4950)

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

src/components/graph/selectionToolbox/ConvertToSubgraphButton.vue

@@ -1,6 +1,20 @@
 <template>
   <Button
-    v-show="isVisible"
+    v-if="isUnpackVisible"
+    v-tooltip.top="{
+      value: t('commands.Comfy_Graph_UnpackSubgraph.label'),
+      showDelay: 1000
+    }"
+    severity="secondary"
+    text
+    @click="() => commandStore.execute('Comfy.Graph.UnpackSubgraph')"
+  >
+    <template #icon>
+      <i-lucide:expand />
+    </template>
+  </Button>
+  <Button
+    v-else-if="isConvertVisible"
     v-tooltip.top="{
       value: t('commands.Comfy_Graph_ConvertToSubgraph.label'),
       showDelay: 1000
@@ -20,6 +34,7 @@ import Button from 'primevue/button'
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import { SubgraphNode } from '@/lib/litegraph/src/litegraph'
 import { useCommandStore } from '@/stores/commandStore'
 import { useCanvasStore } from '@/stores/graphStore'
 
@@ -27,7 +42,13 @@ const { t } = useI18n()
 const commandStore = useCommandStore()
 const canvasStore = useCanvasStore()
 
-const isVisible = computed(() => {
+const isUnpackVisible = computed(() => {
+  return (
+    canvasStore.selectedItems?.length === 1 &&
+    canvasStore.selectedItems[0] instanceof SubgraphNode
+  )
+})
+const isConvertVisible = computed(() => {
   return (
     canvasStore.groupSelected ||
     canvasStore.rerouteSelected ||