Double chaining leads to a stack overflow

The following expression is useless, since you'd expect the second `chain` call to just return a new wrapper of the same value:

```js
_.chain([1]).chain()
```

but rather than behaving like a no-op, it results in a stack overflow. Credits to @reubenrybnik for pointing this out in https://github.com/DefinitelyTyped/DefinitelyTyped/pull/45201#issuecomment-637696652. This minor pitfall might have been introduced with #1691.

I'm hesitant to give this a "bug" label as it is rather non-urgent, but technically it's a bug. Documenting in an issue ticket for reference.

Reproduce the expression `_.chain([1]).chain()` and inspect the chain implementation and any related tests, using issue #1691 and pull request #2963 as context. Done means the second `chain` call no longer causes a stack overflow and behaves as the issue describes.

Written by the indexing model from the issue text.