Update `complexityAverage` in all branches of static eval
STC: https://tests.stockfishchess.org/tests/view/63dda49573223e7f52ad0f8c
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 117416 W: 31173 L: 31049 D: 55194
Ptnml(0-2): 290, 12246, 33533, 12328, 311
LTC: https://tests.stockfishchess.org/tests/view/63dfa90873223e7f52ad69b8
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 44416 W: 11924 L: 11744 D: 20748
Ptnml(0-2): 5, 4036, 13968, 4172, 27
closes https://github.com/official-stockfish/Stockfish/pull/4385
bench 4758694