test: clarify SubgraphNode test name to distinguish subgraph.configure() vs node.configure() reconfigure paths

## Context

In `src/lib/litegraph/src/subgraph/SubgraphNode.test.ts`, two tests have very similar names that obscure which reconfigure path each exercises:

- **Existing test** (describe: `SubgraphNode duplicate input pruning (#9977)`): `'should not accumulate duplicate inputs on reconfigure'` — uses `node.configure()`
- **New test** (describe: `Nested SubgraphNode duplicate input prevention`): `'should not accumulate inputs across multiple reconfigure cycles'` — uses `subgraph.configure()`

## Proposed Change

Rename the new test to make the distinction explicit, e.g.:

```ts
it('should not accumulate inputs across multiple subgraph.configure() cycles', () => {
```

This was raised as a non-blocking nitpick during review of PR #10187 by @christian-byrne.

## References
- PR: https://github.com/Comfy-Org/ComfyUI_frontend/pull/10187
- Review comment: https://github.com/Comfy-Org/ComfyUI_frontend/pull/10187#discussion_r2947987108
- Requested by: @christian-byrne

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10191-test-clarify-SubgraphNode-test-name-to-distinguish-subgraph-configure-vs-node-conf-3266d73d3650815b9194fc06aa98dd3c) by [Unito](https://www.unito.io)