Extract exception message from chain for API errors (#2100)

* Get message from excepiton chain

* cleanup

tests/utils/test_exception_helper.py

@@ -1,6 +1,6 @@
 """Test exception helpers."""
 
-from supervisor.utils import check_exception_chain
+from supervisor.utils import check_exception_chain, get_message_from_exception_chain
 
 
 def test_simple_chain_exception():
@@ -55,3 +55,33 @@ def test_list_nested_chain_exception_not():
             raise KeyError() from err
     except KeyError as err:
         assert not check_exception_chain(err, (AssertionError, OSError))
+
+
+def test_simple_chain_exception_message():
+    """Test simple chain of excepiton."""
+
+    try:
+        raise ValueError("error")
+    except ValueError as err:
+        assert get_message_from_exception_chain(err) == "error"
+
+
+def test_simple_chain_exception_not_message():
+    """Test simple chain of excepiton."""
+
+    try:
+        raise ValueError()
+    except ValueError as err:
+        assert not get_message_from_exception_chain(err)
+
+
+def test_simple_nested_chain_exception_message():
+    """Test simple nested chain of excepiton."""
+
+    try:
+        try:
+            raise ValueError("error")
+        except ValueError as err:
+            raise KeyError() from err
+    except KeyError as err:
+        assert get_message_from_exception_chain(err) == "error"