chore: refactor topic_delete_transaction to use Client.from_env() (hiero-ledger#1971)

Signed-off-by: greywolf8 <arkapravapanigrahi798080@gmail.com>

Author: greywolf8

CHANGELOG.md

@@ -21,6 +21,8 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 ### Examples
 - Updated the `examples/consensus/topic_create_transaction_revenue_generating.py` example to use `Client.from_env()` for simpler client setup. (#1964)
 
+- Refactored `examples/consensus/topic_delete_transaction.py` to use Client.from_env() for simplified client initialization, removed manual setup code, and cleaned up unused imports (`os`, `AccountId`, `PrivateKey`). (`#1971`)
+
 ### Tests
 
 ### Docs

examples/consensus/topic_delete_transaction.py

@@ -9,47 +9,27 @@
 - topic_delete_transaction() performs the create+delete transaction steps
 - main() orchestrates setup and calls helper functions
 """
-import os
-import sys
 
-from dotenv import load_dotenv
+import sys
 
 from hiero_sdk_python import (
-    AccountId,
     Client,
-    Network,
-    PrivateKey,
     ResponseCode,
     TopicCreateTransaction,
     TopicDeleteTransaction,
 )
+from hiero_sdk_python.account.account_id import AccountId
+from hiero_sdk_python.crypto.private_key import PrivateKey
 
-load_dotenv()
-network_name = os.getenv("NETWORK", "testnet").lower()
-
-
-def setup_client():
-    """Initialize and set up the client with operator account."""
-    print(f"🌐 Connecting to Hedera {network_name}...")
-    network = Network(network_name)
-    print(f"Connecting to Hedera {network_name} network!")
-    client = Client(network)
 
-    try:
-        operator_id_str = os.getenv("OPERATOR_ID")
-        operator_key_str = os.getenv("OPERATOR_KEY")
-        if not operator_id_str or not operator_key_str:
-            print("Error: OPERATOR_ID or OPERATOR_KEY not set in .env file")
-            sys.exit(1)
-        operator_id = AccountId.from_string(operator_id_str)
-        operator_key = PrivateKey.from_string(operator_key_str)
-        client.set_operator(operator_id, operator_key)
-        print(f"Client set up with operator id {client.operator_account_id}")
-
-        return client, operator_id, operator_key
-    except (TypeError, ValueError):
-        print("Error: Creating client, Please check your .env file")
-        sys.exit(1)
+def setup_client() -> tuple[Client, AccountId, PrivateKey]:
+    """
+    Set up and configure the client by loading OPERATOR_ID and OPERATOR_KEY with Client.from_env().
+    """
+    client = Client.from_env()
+    print(f"Connecting to Hedera {client.network.network} network!")
+    print(f"Client set up with operator id {client.operator_account_id}")
+    return client, client.operator_account_id, client.operator_private_key
 
 
 def create_topic(client, operator_key):