fix: no chunk-only producer in stateless validation (#11561)

We had this code change that forced 20 block producers on chain ids that
are not mainnet. However, it makes no sense in stateless validation
where there is no chunk-only producers. Fixed this by introducing a new
protocol version.

core/primitives-core/src/version.rs

@@ -168,6 +168,8 @@ pub enum ProtocolFeature {
     WitnessTransactionLimits,
     /// Size limit on outgoing receipts.
     OutgoingReceiptsSizeLimit,
+    /// No chunk-only producers in stateless validation
+    NoChunkOnlyProducers,
 }
 
 impl ProtocolFeature {
@@ -233,7 +235,8 @@ impl ProtocolFeature {
             ProtocolFeature::WitnessTransactionLimits
             | ProtocolFeature::CongestionControl
             | ProtocolFeature::OutgoingReceiptsSizeLimit => 87,
-            ProtocolFeature::CongestionControlAllowedShardValidation => 88,
+            ProtocolFeature::CongestionControlAllowedShardValidation
+            | ProtocolFeature::NoChunkOnlyProducers => 88,
 
             // Nightly features
             #[cfg(feature = "protocol_feature_fix_staking_threshold")]

core/primitives/src/epoch_manager.rs

@@ -261,6 +261,7 @@ impl AllEpochConfig {
         // mainnet, to make it easier to test the change.
         if chain_id != near_primitives_core::chains::MAINNET
             && checked_feature!("stable", TestnetFewerBlockProducers, protocol_version)
+            && !checked_feature!("stable", NoChunkOnlyProducers, protocol_version)
         {
             let shard_ids = config.shard_layout.shard_ids();
             // Decrease the number of block producers from 100 to 20.
@@ -270,6 +271,11 @@ impl AllEpochConfig {
             // Decrease the number of chunk producers.
             config.validator_selection_config.num_chunk_only_producer_seats = 100;
         }
+
+        if checked_feature!("stable", NoChunkOnlyProducers, protocol_version) {
+            // Make sure there is no chunk only producer in stateless validation
+            config.validator_selection_config.num_chunk_only_producer_seats = 0;
+        }
     }
 
     fn config_max_kickout_stake(config: &mut EpochConfig, protocol_version: u32) {