Fix proper joining of the path for logs retrieved from celery workers (…

…apache#26493)

The change apache#26377 "fixed" the way how logs were retrieved from
Celery, but it - unfortunately broke the retrieval eventually.

This PR should fix it.

Fixes: apache#26492
(cherry picked from commit 52560b8)

airflow/utils/log/file_task_handler.py

@@ -190,7 +190,8 @@ def _read(self, ti, try_number, metadata=None):
             import httpx
 
             url = urljoin(
-                f"http://{ti.hostname}:{conf.get('logging', 'WORKER_LOG_SERVER_PORT')}/log", log_relative_path
+                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"