test(firecracker): satisfy pyright on the new infra-VM tests

Two lint fixes, both test-only (no effect on the infra artifact version):
- annotate the TestAdoptable / TestKillInfraFirecrackers helper params
  (reportMissingParameterType).
- test_docker_test_helpers: read __unittest_skip__ via getattr on the
  dynamically-built Case type, matching the sibling assertion — pyright can't
  see the attribute the skip decorator adds (reportAttributeAccessIssue).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A9qa3xoavjQScufDfZaXKR

tests/unit/test_docker_test_helpers.py

@@ -28,7 +28,7 @@ class TestSkipUnlessDockerOrFirecracker(unittest.TestCase):
         ):
             decorated = skip_unless_docker_or_firecracker()(type("Case", (), {}))
 
-        self.assertTrue(decorated.__unittest_skip__)
+        self.assertTrue(getattr(decorated, "__unittest_skip__", False))
 
 
 if __name__ == "__main__":

tests/unit/test_firecracker_infra_vm.py

@@ -219,7 +219,7 @@ class TestKillPidfile(unittest.TestCase):
 
 
 class TestAdoptable(unittest.TestCase):
-    def _dir(self, td, *, key=True, version=None):
+    def _dir(self, td: str, *, key: bool = True, version: str | None = None) -> Path:
         d = Path(td)
         if key:
             (d / "id_ed25519").write_text("k")
@@ -259,7 +259,7 @@ class TestAdoptable(unittest.TestCase):
 
 
 class TestKillInfraFirecrackers(unittest.TestCase):
-    def _fake_proc(self, root, pid, comm, cmdline):
+    def _fake_proc(self, root: Path, pid: int, comm: str, cmdline: list[str]) -> None:
         p = root / str(pid)
         p.mkdir()
         (p / "comm").write_text(comm + "\n")