fix: remove test passing None to non-nullable memory_space_id

The test_returns_none_when_no_space_id test passed None to
_check_escalation_memory_cache which now requires str. The None
guard is at the call site, so this test is no longer applicable.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mjnovice

tests/agent/tools/test_escalation_memory.py

@@ -33,11 +33,6 @@ def test_returns_none_when_no_space_id(self) -> None:
 
 
 class TestCheckEscalationMemoryCache:
-    @pytest.mark.asyncio
-    async def test_returns_none_when_no_space_id(self) -> None:
-        result = await _check_escalation_memory_cache(None, {"key": "value"})
-        assert result is None
-
     @pytest.mark.asyncio
     @patch("uipath_langchain.agent.tools.escalation_tool.UiPath")
     async def test_returns_cached_answer(self, mock_uipath_cls: MagicMock) -> None: