Remove priority from vote transactions (solana-labs#28030)

vote transactions have same priority fee

core/src/immutable_deserialized_packet.rs

@@ -53,10 +53,15 @@ impl ImmutableDeserializedPacket {
         let is_simple_vote = packet.meta.is_simple_vote_tx();
 
         // drop transaction if prioritization fails.
-        let priority_details = priority_details
+        let mut priority_details = priority_details
             .or_else(|| sanitized_transaction.get_transaction_priority_details())
             .ok_or(DeserializedPacketError::PrioritizationFailure)?;
 
+        // set priority to zero for vote transactions
+        if is_simple_vote {
+            priority_details.priority = 0;
+        };
+
         Ok(Self {
             original_packet: packet,
             transaction: sanitized_transaction,