[Feature] Access Electron context menu in test

Nobody has claimed this yet.

I didn't found any way to access a context menu that is generated in the renderer process via the Remote module.

The renderer JS under test looks like this:

```javascript
"use strict"

const remote = require("@electron/remote")

function handleContextMenuEvent() {
const menu = new remote.Menu()
if (window.getSelection().toString()) {
menu.append(
new remote.MenuItem({
label: "Copy selection",
role: "copy",
})
)
menu.popup({
window: remote.getCurrentWindow(),
})
}
}

document.addEventListener("DOMContentLoaded", () => {
document.getElementById("text-area").innerText = "This is a test"
})

window.addEventListener("contextmenu", handleContextMenuEvent)
```

Neither [Playwright's](https://playwright.dev/docs/api/class-playwright) nor [Electron's](https://www.electronjs.org/docs/latest/api/menu) documentation seems to show any way to access a menu that is not the application main menu.

I assume after my unsuccessful research that this feature is missing. Maybe such a feature is in the responsibility of the Electron team but I only need this for E2E testing.

I made a [demo project](https://github.com/c3er/electron-contextmenu) with this context menu approach.

Start with the renderer JavaScript shown in the issue and the linked Electron context-menu demo, then compare the available Playwright Electron and Electron Menu APIs. Define how an end-to-end test should access a context menu created in the renderer process, and verify that the menu can be observed or interacted with.

Written by the indexing model from the issue text.