lnd: don't wait until the RPC port is open after unlocking

According to the release notes of lnd 0.13.0 [0] the RPC service is available at
all times.

[0] https://github.com/lightningnetwork/lnd/releases/tag/v0.13.0-beta

modules/lnd.nix

@@ -239,11 +239,6 @@ in {
                 -d "{\"wallet_password\": \"$(cat ${secretsDir}/lnd-wallet-password | tr -d '\n' | base64 -w0)\"}" \
                 ${restUrl}/unlockwallet
             fi
-
-            # Wait until the RPC port is open
-            while ! { exec 3>/dev/tcp/${cfg.rpcAddress}/${toString cfg.rpcPort}; } &>/dev/null; do
-              sleep 0.1
-            done
           '')
           # Setting macaroon permission for other users needs root permissions
           (nbLib.privileged "lnd-create-macaroons" ''