Update image file validation test assertion

The test for image file validation now asserts that the error message does not contain 'file appears to be binary', reflecting a change in expected behavior.

Author: SmartManoj

tests/tools/file_editor/test_file_validation.py

@@ -100,4 +100,4 @@ def test_validate_image_file(tmp_path):
     with pytest.raises(FileValidationError) as exc_info:
         editor.validate_file(image_file)
 
-    assert "file appears to be binary" in str(exc_info.value).lower()
+    assert "file appears to be binary" not in str(exc_info.value).lower()