I don't think it was. Sansa made a point to say a dragon and a chunk of the army is already out. That far from implies Dany will suddenly take Cersei out quick, or that she had the means to given the Dragons aren't the trump card she thought.
Jaime is not going back to hold hands with cersei, he's going to end the root of everything that makes him a bad person. I thought that was made extremely clear at the scene with Brienne. Unless I'm shit at interpreting it of course
Edit - I just checked the writers do claim that he's gone because he's addicted to Cersei. That has to be one of the shoodiest pieces of writing ever but I'm less than surprised given their standards.