feat: harden all sporks on mainnet to current values

doc/release-notes-6140.md

@@ -0,0 +1,6 @@
+Mainnet Spork Hardening
+-----------------------
+
+This version hardens all Sporks on mainnet. Sporks remain in effect on all devnets and testnet; however, on mainnet,
+the value of all sporks are hard coded to 0, or 1 for SPORK_21_QUORUM_ALL_CONNECTED. These hardened values match the
+active values historically used on mainnet, so there is no change in the network's functionality.

src/spork.cpp

@@ -262,6 +262,16 @@ bool CSporkManager::IsSporkActive(SporkId nSporkID) const
 
 SporkValue CSporkManager::GetSporkValue(SporkId nSporkID) const
 {
+    // Harden all sporks on Mainnet
+    if (!Params().IsTestChain()) {
+        switch (nSporkID) {
+            case SPORK_21_QUORUM_ALL_CONNECTED:
+                return 1;
+            default:
+                return 0;
+        }
+    }
+
     LOCK(cs);
 
     if (auto opt_sporkValue = SporkValueIfActive(nSporkID)) {