When converting single group to subgraph, also convert children (#5217)

* On conversion of single group, convert children

If convert to subgraph is called on a selection consisting of a single
group, the groups children are also converted to subgraph.

* Update locales [skip ci]

* Create new set to avoid mutating passed argument

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

src/lib/litegraph/src/LGraph.ts

@@ -1482,6 +1482,12 @@ export class LGraph
     if (items.size === 0)
       throw new Error('Cannot convert to subgraph: nothing to convert')
     const { state, revision, config } = this
+    const firstChild = [...items][0]
+    if (items.size === 1 && firstChild instanceof LGraphGroup) {
+      items = new Set([firstChild])
+      firstChild.recomputeInsideNodes()
+      firstChild.children.forEach((n) => items.add(n))
+    }
 
     const {
       boundaryLinks,