fix: don't install contract if it is already installed

cmd/soroban-cli/src/commands/contract/install.rs

@@ -4,6 +4,7 @@ use std::num::ParseIntError;
 
 use clap::{command, Parser};
 use soroban_env_host::xdr::{
+    self,
     Error as XdrError, Hash, HostFunction, InvokeHostFunctionOp, Memo, MuxedAccount, Operation,
     OperationBody, Preconditions, ScMetaEntry, ScMetaV0, SequenceNumber, Transaction,
     TransactionExt, TransactionResult, TransactionResultResult, Uint256, VecM,
@@ -117,6 +118,13 @@ impl NetworkRunnable for Cmd {
 
         let (tx_without_preflight, hash) =
             build_install_contract_code_tx(&contract, sequence + 1, self.fee.fee, &key)?;
+
+
+        let code_key = xdr::LedgerKey::ContractCode(xdr::LedgerKeyContractCode { hash: hash.clone() });
+        let contract_data = client.get_ledger_entries(&[code_key]).await?;
+        if !contract_data.entries.unwrap_or_default().is_empty() {
+            return Ok(hash);
+        }
 
         // Currently internal errors are not returned if the contract code is expired
         if let Some(TransactionResult {