fix(astro): Try-catch controller.close() usage

[mydea]

Hopefully fixes #16491

I could not get a reproducing test there for this 🤔 I figure this is "safe" to do, but not quite sure how/when this would happen. I would assume this was "introduced" by #15995, maybe @Fryuni has a clue how/when that could happen and if this is a reasonable change 🤔

[Fryuni]

The error description indicates that calling enqueue on a closed controller fails, not close. close should be a no-op on an already closed controller.

The controller may be closed by downstream code for multiple reasons, like a canceled request or a closed connection.
In theory once the request is closed we should stop the iterations and close the original stream. But we could just consume it to the end discarding everything.

I think (would have to look at the docs) there is a .closed property we could check before calling enqueue