Remove deprecated Prysm flag

Author: KaloyanTanev

prysm/run.sh

@@ -49,6 +49,5 @@ echo "Imported all keys"
     --enable-beacon-rest-api \
     --beacon-rest-api-provider="${BEACON_NODE_ADDRESS}" \
     --beacon-rpc-provider="${BEACON_NODE_ADDRESS}" \
-    --beacon-rpc-gateway-provider="${BEACON_NODE_ADDRESS}" \
     --"${NETWORK}" \
     --distributed