op-challenger: Fix make alphabet (#7173)

Root claim needs to have the invalid VM status byte set.

op-challenger/scripts/alphabet/init_game.sh

@@ -62,5 +62,7 @@ done
 # Root claim commits to the entire trace.
 # Alphabet game claim construction: keccak256(abi.encode(trace_index, trace[trace_index]))
 ROOT_CLAIM=$(cast keccak $(cast abi-encode "f(uint256,uint256)" 15 122))
+# Replace the first byte of the claim with the invalid vm status indicator
+ROOT_CLAIM="0x01${ROOT_CLAIM:4:60}"
 
 GAME_TYPE=255 ${SOURCE_DIR}/../create_game.sh http://localhost:8545 "${DISPUTE_GAME_FACTORY}" "${ROOT_CLAIM}" --private-key "${DEVNET_SPONSOR}"