Inconsistencies: File upload tests should use query_string for params

[dcblundell]

• Upload tests use f-string query-param concatenation. Most upload tests in backend/ttnn_visualizer/tests/test_file_uploads.py (e.g. :328, :366, :395, :425, :457, :497, :535, :577) build the URL as f"/api/local/upload/...?instanceId={instance_id}" rather than the query_string={...} form. The instanceId value is UUID-like so this happens to be encoding-safe, but the form drifts from the Testing-section rule. Pre-existing; new tests should use query_string={...}.