fix(backend): update test mock to return 4-value tuple from validate_and_construct_node_execution_input

The function now returns (graph, starting_nodes_input, compiled_nodes_input_masks, nodes_to_skip)
to support the optional credentials feature.

Co-authored-by: Nicholas Tindle <ntindle@users.noreply.github.com>

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

autogpt_platform/backend/backend/executor/utils_test.py

@@ -367,10 +367,13 @@ async def test_add_graph_execution_is_repeatable(mocker: MockerFixture):
     )
 
     # Setup mock returns
+    # The function returns (graph, starting_nodes_input, compiled_nodes_input_masks, nodes_to_skip)
+    nodes_to_skip: set[str] = set()
     mock_validate.return_value = (
         mock_graph,
         starting_nodes_input,
         compiled_nodes_input_masks,
+        nodes_to_skip,
     )
     mock_prisma.is_connected.return_value = True
     mock_edb.create_graph_execution = mocker.AsyncMock(return_value=mock_graph_exec)