This function has been copied from various projects, where it is common
to transform an enum into another data structure. For instance:

```
enum InfuraNetworkType {
  mainnet = 'mainnet',
  goerli = 'goerli',
  sepolia = 'sepolia',
}

const infuraNetworkClientConfigurations =
  Object.keys(InfuraNetworkType).map((network) => {
    const networkClientId = buildInfuraNetworkClientId(network);
    const networkClientConfiguration = {
      type: NetworkClientType.Infura,
      network,
      infuraProjectId: this.#infuraProjectId,
    };
    return [networkClientId, networkClientConfiguration];
  });
```

As the above example, one could use `Object.keys()` or even
`Object.getOwnPropertyNames()` to obtain said properties. A problem
occurs, however, if the type of the properties of the resulting object
needs to match the type of the properties in the enum, that means the
variable inside the loop needs to be of that type, too. Both
`Object.keys()` and `Object.getOwnPropertyNames()` are intentionally
generic: they returns the property names of an object, but neither can
make guarantees about the contents of that object, so the type of the
property names is merely `string[]`. While this is technically accurate,
we don't have to be so cautious in these situations, because we own
the object in question and therefore know exactly which properties it
has.

This commit adds a `getKnownPropertyNames` function which is like
`Object.getOwnPropertyNames()` except that the resulting array of
property names will be typed using the types of the properties of the
given object. In the above example that would mean that `network` would
have a type of `InfuraNetworkType` and not `string`.

Co-authored-by: Maarten Zuidhoorn <maarten@zuidhoorn.com>