Want me to tell you how to avoid that and also damaging the brake rotor?
When you get the bearing and the new pulley on the shaft, all you need is the one thin washer in the kit before you try to slip the retainer clip on there. At this point, use your wide-blade screwdriver in the slot where the clip would go in, and with the screwdriver in the slot on one side, turn it ever so slightly or lift up on it to press the washer up further, then slip the clip on with your other hand. The clip just needs to be at the slot opening, because the next step is to take the needle nose pliers and gently grip the shaft and the far end of the c-clip and squeeze them together.
Easier than trying to balance a pry tool in one hand and do all that, no risk of rotor harm.