`e2e_default_model_with_session_routes_to_proxy` and
`e2e_duplicate_model_field_both_entries_survive` assert the default
model's base URL. They were not serial and read `KIGI_CODE_BASE_URL`
through `EndpointsConfig`, while two serial tests (auth_method.rs,
models_fetch.rs) point that variable at wiremock. When the runs
overlapped, the base URL came back as the wiremock URI: the Linux suite
failed in 2 of 13 full runs. Presetting the variable fails both tests
every time, on v0.1.15 as well.
Both tests are now `#[serial]` and unset the variable for their scope,
the same cure `e2e_enterprise_endpoints_only_no_model_override` got for
the moonshot variable. With the variable preset they pass.
ZacharyZhang-NY
256ff2528e