incomplete fix for 25+5 with React@18 in #1485

[jeremyagray]

Issue #1485 missed this line. This appears to only affect projects that decrement the session counter with this.setState(state => {...}) and not with this.setState(newState) (see examples for React 16 (passes break countdown reaches zero test), 17 (passes), and 18 (same code, but fails), current post (fails) in the fCC forums, and this project (passes) from the forums that uses the newState method). From the rest of the fix, it seems that this line was inadvertently left behind.

Deleting the line in question and rebuilding the bundle fixed the problem locally for all five (all pass the test, as expected) of the above referenced projects.