[3.12] gh-106123: Modules/_sha3 appears to no longer be necessary (GH-106124) (#106127)

Co-authored-by: Skip Montanaro <[email protected]>

Author: miss-islington

configure

@@ -6697,7 +6697,6 @@ SRCDIRS="\
   Modules/_hacl \
   Modules/_io \
   Modules/_multiprocessing \
-  Modules/_sha3 \
   Modules/_sqlite \
   Modules/_sre \
   Modules/_testcapi \