Support `ts`, `mts` and `cts` files by default

Ever since `--experimental-strip-types` got unflagged, node:test now also runs typescript files by default. The extension should be updated to account for this

I currently have to use the following config to get around it:
```json
"nodejs-testing.extensions": [
{
"extensions": ["ts"],
"parameters": []
}
],
```

Ref: https://nodejs.org/api/test.html#running-tests-from-the-command-line