Properly build URL to retrieve logs independently from system (#26337)

The previous way of building the path depended on the OS path
but it was really used to build the URL so we should use
urllib instead of os.path.join.

(cherry picked from commit 1838602)

airflow/utils/log/file_task_handler.py

@@ -21,6 +21,7 @@
 import warnings
 from pathlib import Path
 from typing import TYPE_CHECKING, Optional
+from urllib.parse import urljoin
 
 from airflow.configuration import AirflowConfigException, conf
 from airflow.exceptions import RemovedInAirflow3Warning
@@ -194,8 +195,8 @@ def _read(self, ti, try_number, metadata=None):
         else:
             import httpx
 
-            url = os.path.join("http://{ti.hostname}:{worker_log_server_port}/log", log_relative_path).format(
-                ti=ti, worker_log_server_port=conf.get('logging', 'WORKER_LOG_SERVER_PORT')
+            url = urljoin(
+                f"http://{ti.hostname}:{conf.get('logging', 'WORKER_LOG_SERVER_PORT')}/log", log_relative_path
             )
             log += f"*** Log file does not exist: {location}\n"
             log += f"*** Fetching from: {url}\n"