Stop forcing block time to 2000 when anvil runs on 1 second block tim…

…es (#469)

original change here:
8a30c66

maybe this is why ci is unstable

the default was moved from another file, but with the unintentional
consequence that it superseded the previous default of 1 sec


Related - i'm updating the scripts to pipe the block time var through to
everything here https://github.com/river-build/river/pull/470/files

core/node/run_impl.sh

@@ -15,7 +15,6 @@ export RPC_PORT="${RPC_PORT:-5170}"
 export DISABLE_BASE_CHAIN="${DISABLE_BASE_CHAIN:-false}"
 export RIVER_ENV="local_${RUN_ENV}"
 export POSITIVE_ENTITLEMENT_CACHE_TTL_SECONDS="${POSITIVE_ENTITLEMENT_CACHE_TTL_SECONDS:-5}"
-export BLOCK_TIME_MS=${BLOCK_TIME_MS:-2000}
 export ENABLE_DEBUG_ENDPOINTS=true
 
 [ -z "${BLOCK_TIME_MS+x}" ] && BLOCK_TIME_MS=$(( ${RIVER_BLOCK_TIME:-1} * 1000 ))