fix(token-counter): fix test isolation and encode() return type normalization

Two independent fixes for test_token_counter.py failures in CI:

1. test_disable_hf_tokenizer_download leaked litellm.disable_hf_tokenizer_download=True
   because pytest.MonkeyPatch() was never undone. The setting persisted into the
   alphabetically-subsequent test_llama2/3_tokenizer_api_failure tests, causing
   _select_tokenizer_helper to short-circuit before calling from_pretrained.
   Fix: wrap the test body in try/finally and call monkeypatch.undo().

2. encode() returns a HuggingFace Encoding object when the HF tokenizer loads, but
   falls back to returning a plain List[int] (tiktoken) when the model hub is
   unreachable. test_encoding_and_decoding called .ids on the result, which raises
   AttributeError when the list-based fallback is active.
   Fix: normalize encode() to always return List[int] by extracting .ids when present,
   and remove the now-unnecessary .ids access in the test.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_litellm/litellm_core_utils/test_token_counter.py

@@ -582,14 +582,15 @@ class TestTokenizerSelection(unittest.TestCase):
 
     @patch("litellm.utils._return_huggingface_tokenizer")
     def test_disable_hf_tokenizer_download(self, mock_return_huggingface_tokenizer):
-        # Use pytest.MonkeyPatch() directly instead of fixture
         monkeypatch = pytest.MonkeyPatch()
         monkeypatch.setattr(litellm, "disable_hf_tokenizer_download", True)
-
-        result = _select_tokenizer_helper("grok-32r22r")
-        mock_return_huggingface_tokenizer.assert_not_called()
-        assert result["type"] == "openai_tokenizer"
-        assert result["tokenizer"] == encoding
+        try:
+            result = _select_tokenizer_helper("grok-32r22r")
+            mock_return_huggingface_tokenizer.assert_not_called()
+            assert result["type"] == "openai_tokenizer"
+            assert result["tokenizer"] == encoding
+        finally:
+            monkeypatch.undo()
 
 
 @pytest.mark.parametrize(