ICC will do nothing.
They will sit back and let the Boards thrash it out.
Usual tactics from a weak organisation.
I have been saying before and I'll say it again. ICC has been incredibly weak in helping cricket bring to Pakistan. They've done less than bare minimum. Other sporting bodies have been far more helpful to other countries in similar situations.
They don't have to force other countries to visit to Pakistan, but they can strongly push them to visit Pakistan, to the point where the other boards feel pressure. But, they have basically sat back and done very little. Most things get done not by forcing one party or the other but by building pressure. If ICC had done its job properly, we probably would've returned to Pakistan a long time ago.
And before some genius Einstein's does a gotcha "maybe PCB could've done their job and not have the SL team attacked", yes, they should have. It does not absolve ICC their job in helping cricket come back.