list Stakecore provider for Flare (#384)

Author: kuco23

bifrost-wallet.providerlist.json

@@ -1970,7 +1970,8 @@
       "description": "An infrastructure provider that recognizes the importance of reliable data for an oracle-based chain.",
       "url": "https://stakecore.org",
       "address": "0x1e68DC808A240C096F0261144dc41fd4c883Cfb0",
-      "logoURI": "https://raw.githubusercontent.com/TowoLabs/ftso-signal-providers/master/assets/0x1e68DC808A240C096F0261144dc41fd4c883Cfb0.png"
+      "logoURI": "https://raw.githubusercontent.com/TowoLabs/ftso-signal-providers/master/assets/0x1e68DC808A240C096F0261144dc41fd4c883Cfb0.png",
+      "listed": true
     },
     {
       "chainId": 14,