Fix TestRemoveDanglingTasks (#3426)

Unset SERVER_KEEP_SHIM_TASKS

Author: un-def

src/tests/_internal/server/background/tasks/test_process_instances.py

@@ -396,7 +396,7 @@ async def test_check_shim_check_instance_health(self, test_db, session: AsyncSes
         assert health_check.response == health_response.json()
 
 
-@pytest.mark.usefixtures("disable_maybe_install_components")
+@pytest.mark.usefixtures("disable_maybe_install_components", "turn_off_keep_shim_tasks_setting")
 class TestRemoveDanglingTasks:
     @pytest.fixture
     def disable_maybe_install_components(self, monkeypatch: pytest.MonkeyPatch) -> None:
@@ -405,6 +405,10 @@ def disable_maybe_install_components(self, monkeypatch: pytest.MonkeyPatch) -> N
             Mock(return_value=None),
         )
 
+    @pytest.fixture
+    def turn_off_keep_shim_tasks_setting(self, monkeypatch: pytest.MonkeyPatch) -> None:
+        monkeypatch.setattr("dstack._internal.server.settings.SERVER_KEEP_SHIM_TASKS", False)
+
     @pytest.fixture
     def ssh_tunnel_mock(self) -> Generator[Mock, None, None]:
         with patch("dstack._internal.server.services.runner.ssh.SSHTunnel") as SSHTunnelMock: