dockerfile: reduce interval and env config

- bitcoind and cln reduce healthcheck time interval
- cln healthcheck no need to use switch case instead use VLS_NETWORK
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

lightningd/healthcheck.sh

@@ -2,13 +2,4 @@
 
 set -ex
 
-LIGHTNING_NETWORK=""
-
-case $BITCOIN_CHAIN in
-    "test")    LIGHTNING_NETWORK=testnet ;;
-    "regtest") LIGHTNING_NETWORK=regtest ;;
-    "signet")  LIGHTNING_NETWORK=signet ;;
-    *) echo "Invalid BITCOIN_CHAIN value: $BITCOIN_CHAIN" && exit 1 ;;
-esac
-
-lightning-cli --network $LIGHTNING_NETWORK getinfo
+lightning-cli --network $VLS_NETWORK summary