This patch adds support for listing `worker scripts` in `debugger >
source` panel
For example:
```
<!-- test.html -->
<!doctype html><meta charset=utf-8>
<script>
setTimeout(() => {
console.log("inline classic");
new Worker("worker.js");
const blob = new Blob([`console.log("blob worker");`], { type: "text/javascript" });
const blobURL = URL.createObjectURL(blob);
new Worker(blobURL);
}, 2000);
</script>
```
```
// worker.js
console.log("external classic worker");
```
```
./mach run --devtools=6080 http://127.0.0.1:3000/test.html
```

Another example:
```
./mach run --devtools=6080 https://charming.daz.cat/
```

- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes partially implement #36027
- [x] These changes require tests, but they are blocked on
https://github.com/servo/servo/issues/36325
---------
Signed-off-by: atbrakhi <atbrakhi@igalia.com>