Bump torchao pin to include lazy x86 import fix (pytorch/ao#4013) (#17984)

### Summary
update to latest main. 

42bcdc491 (HEAD, origin/main, origin/HEAD) [CPU] Skip broken test cases
with torch nightly (#4014)
c17160a35 Fix broken imports on macOS (#4013)

### Test plan
ci

Co-authored-by: Github Executorch <github_executorch@arm.com>

Author: lucylq