Fixed UnknownHostException on the specified KeyVault (#3102)

Fix #3090

Author: nfx

src/databricks/labs/ucx/assessment/secrets.py

@@ -3,7 +3,7 @@
 import re
 
 from databricks.sdk import WorkspaceClient
-from databricks.sdk.errors import NotFound
+from databricks.sdk.errors import NotFound, InvalidState
 
 logger = logging.getLogger(__name__)
 
@@ -24,6 +24,10 @@ def _get_secret_if_exists(self, secret_scope, secret_key) -> str | None:
         except NotFound:
             logger.warning(f'removed on the backend: {secret_scope}/{secret_key}')
             return None
+        except InvalidState as e:
+            # see https://github.com/databrickslabs/ucx/issues/3090
+            logger.warning(f'Invalid Azure Key Vault for {secret_scope}/{secret_key}: {e}')
+            return None
         except UnicodeDecodeError:
             logger.warning(
                 f"Secret {secret_scope}/{secret_key} has Base64 bytes that cannot be decoded to utf-8 string."