The plan to capture Rand has existed since early in the series.

The link to Moridin, in turn, was never planned for by the Shadow. It was a random event, caused by the crossing of the balefire streams in CoS. And its effects are still being discovered by both parties as they go along.

So I have three problems with the idea that this event was planned by the Shadow:

1. Did Moridin have any idea that Rand could access the True Power through their link?

2. If so, did he share this with the Dark One?

3. How did they know the situation would play out in such a way that Rand would draw on the True Power?

4. Why would they not rather have Rand captured, under their power at Shayol Ghul, where they could break him in far more inventive ways, and get him to eventually access the True Power by swearing to the Dark One himself?

Too many coincidences in the above for it to be a reasonable plot by the Shadow, in my view.