Use DeploymentEnabled to hide VB deployments

The helper was previously unused. This commit changes it to be more
meaningful and puts it to use.

See previous discussion at https://github.com/bitcoin/bitcoin/pull/19438/files#r650687320

src/deploymentstatus.h

@@ -49,7 +49,7 @@ inline bool DeploymentEnabled(const Consensus::Params& params, Consensus::Buried
 inline bool DeploymentEnabled(const Consensus::Params& params, Consensus::DeploymentPos dep)
 {
     assert(Consensus::ValidDeployment(dep));
-    return params.vDeployments[dep].nTimeout != 0;
+    return params.vDeployments[dep].nStartTime != Consensus::BIP9Deployment::NEVER_ACTIVE;
 }
 
 #endif // BITCOIN_DEPLOYMENTSTATUS_H

src/rpc/blockchain.cpp

@@ -1350,8 +1350,7 @@ static RPCHelpMan verifychain()
 static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, UniValue& softforks, const Consensus::Params& params, Consensus::BuriedDeployment dep)
 {
     // For buried deployments.
-    // Buried deployments with activation height value of
-    // std::numeric_limits<int>::max() are disabled and thus hidden.
+
     if (!DeploymentEnabled(params, dep)) return;
 
     UniValue rv(UniValue::VOBJ);
@@ -1366,8 +1365,8 @@ static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, UniValue&
 static void SoftForkDescPushBack(const CBlockIndex* active_chain_tip, UniValue& softforks, const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
 {
     // For BIP9 deployments.
-    // Deployments that are never active are hidden.
-    if (consensusParams.vDeployments[id].nStartTime == Consensus::BIP9Deployment::NEVER_ACTIVE) return;
+
+    if (!DeploymentEnabled(consensusParams, id)) return;
 
     UniValue bip9(UniValue::VOBJ);
     const ThresholdState thresholdState = g_versionbitscache.State(active_chain_tip, consensusParams, id);