test: include column side in the SDK layout contract
The deterministic SDK generator suite fails its exact new-pane-right contract assertion because the expected fields omit the existing optional side parameter. Add its ColumnSide type, nullability, protocol version, and column-left-v1 capability to the expectation, restoring the checks that gate generated SDK validation. Product behavior and the wire schema are unchanged.
The field was introduced with the column-left feature in 698b3ef64cf, including runtime handling, the SDK schema, and generated bindings. The separate consent-method regeneration in #27438 did not touch this contract. This fixes the hand-maintained test expectation, not generated output.
Validation: the named test fails on base 41aa452c580215c1408a8b4607f1d9733e210faf (run 40934884052); the complete 64-test generator suite passes on this head (40935068864). The earlier base/head reproduction also matched by test name and error under scripts/ci/test_reds.py.
Agent session: agent session