chore(tests): remove stale test_init.py cookiecutter leftover

The lone test (`test_router`) has been failing for the lifetime of
the repo. It's `@pytest.mark.asyncio`-decorated but the project
deliberately doesn't ship `pytest-asyncio` (newer tests use
`asyncio.run` inside the body — see `test_cassette_state_consumer.py`
header), so the test is uncollectable in our runner. The body asserts
nothing the extension-load boot path doesn't already cover.

After this: full suite is 155/155 green. Closes #34.

tests/test_init.py

@@ -1,11 +0,0 @@
-import pytest
-from fastapi import APIRouter
-
-from .. import satmachineadmin_ext
-
-
-# just import router and add it to a test router
-@pytest.mark.asyncio
-async def test_router():
-    router = APIRouter()
-    router.include_router(satmachineadmin_ext)