Buttons for dynamic drop-down blocks in playground are broken

[BeksOmega]

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Description

The buttons attempt to call a prompt function that doesn't exist.

Reproduction steps

1. Switch to the test blocks in the playground.
2. Open up the dropdown block tests.
3. Try the "Add option" button. Observe the error.

Stack trace

index.js:2 Uncaught TypeError: t.prompt is not a function
    at c (index.js:2:23634)
    at FlyoutButton.onMouseUp (flyout_button.ts:339:9)
    at SVGGElement.wrapFunc (browser_events.ts:63:14)

Screenshots

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Browsers

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[maribethb]

This was a bug in the block-test plugin, not core. It was already fixed in blockly-samples. Core isn't using the latest fixed version. RaspberryPiFoundation/blockly-samples#2344