Reduce azure.identity logging verbosity

This logs a lot of DEBUG output around token retrieval.

Author: steventux

manage_breast_screening/config/settings.py

@@ -239,6 +239,11 @@ def list_env(key):
         "level": "DEBUG",
     },
     "loggers": {
+        "azure.identity": {
+            "level": "WARNING",
+            "handlers": ["console"],
+            "propagate": False,
+        },
         "django": {
             "level": "INFO",
             "handlers": ["console"],