Revert "use cost model to limit new account creation (#21369)"

This reverts commit 90f41fd9b7.

accountsdb-plugin-postgres/src/postgres_client/postgres_client_transaction.rs

@@ -330,7 +330,6 @@ pub enum DbTransactionErrorCode {
     WouldExceedMaxBlockCostLimit,
     UnsupportedVersion,
     InvalidWritableAccount,
-    WouldExceedMaxAccountDataCostLimit,
 }
 
 impl From<&TransactionError> for DbTransactionErrorCode {
@@ -359,9 +358,6 @@ impl From<&TransactionError> for DbTransactionErrorCode {
             TransactionError::WouldExceedMaxBlockCostLimit => Self::WouldExceedMaxBlockCostLimit,
             TransactionError::UnsupportedVersion => Self::UnsupportedVersion,
             TransactionError::InvalidWritableAccount => Self::InvalidWritableAccount,
-            TransactionError::WouldExceedMaxAccountDataCostLimit => {
-                Self::WouldExceedMaxAccountDataCostLimit
-            }
         }
     }
 }