Newer `terser` breaks the production build

After updating dependencies in https://github.com/jupyterlite/pyodide-kernel/pull/226, starting a new kernel using a production of `jupyterlite-pyodide-kernel` fails with:

```
Failed to construct 'Worker': Failed to read the 'type' property from 'WorkerOptions':
Cannot convert object to primitive value
```

In `packages/pyodide-kernel/src/kernel.ts`, workers are created with:

```javascript
new Worker(new URL('./comlink.worker.js', import.meta.url), {
type: 'module',
})
```

Looking more closely at the built assets:

**Dev:**

```javascript
new Worker(new URL(...), {
type: undefined,
})
```

**Prod (minified):**

```javascript
new Worker(new URL(...), {
type: s, // Variable reused - 's' is the pypi import namespace object
})
```

This seems to be caused by a new version of `terser`, which likely introduced more aggressive variable reuse optimizations.

The UI tests didn't catch this because they were using the dev build, where the issue doesn't manifest.