Remove propTypes.children from PageEndCTA
Remove propTypes.children from PageEndCTA

It's possible for props.children to be an array instead of an object, e.g. if multiple elements w/ no parent are provided; react currently complains about this w/ propTypes defined. I don't think there's a way to specify that a prop contain either an object *or* an array, so we should probably just remove it from propTypes.
mrinaljain/teach.webmaker.org,alicoding/teach.mozilla.org,mozilla/teach.webmaker.org,alicoding/teach.mozilla.org,Pomax/teach.mozilla.org,Pomax/teach.webmaker.org,mmmavis/teach.mozilla.org,PaulaPaul/teach.mozilla.org,toolness/teach.webmaker.org,mozilla/teach.webmaker.org,mrinaljain/teach.webmaker.org,cadecairos/teach.mozilla.org,fredericksilva/teach.webmaker.org,alicoding/teach.webmaker.org,mozilla/teach.mozilla.org,Pomax/teach.webmaker.org,mmmavis/teach.webmaker.org,mozilla/teach.mozilla.org,toolness/teach.webmaker.org,cadecairos/teach.mozilla.org,mmmavis/teach.webmaker.org,AnthonyBobsin/teach.webmaker.org,mmmavis/teach.mozilla.org,Pomax/teach.mozilla.org,mozilla/learning.mozilla.org,asdofindia/teach.webmaker.org,PaulaPaul/teach.mozilla.org,alicoding/teach.webmaker.org,fredericksilva/teach.webmaker.org,emmairwin/teach.webmaker.org,AnthonyBobsin/teach.webmaker.org,emmairwin/teach.webmaker.org,asdofindia/teach.webmaker.org