test: fix broken tests after refactor

- Update test_openbb_service to import from obb_utils (to_list,
  first_or_empty) instead of removed _to_dicts/_first_or_empty
- Update test_stock_upgrades to mock openbb_service instead of
  finnhub_service (upgrades moved to yfinance)

tests/test_openbb_service.py

@@ -1,4 +1,4 @@
-from openbb_service import _to_dicts, _first_or_empty
+from obb_utils import to_list, first_or_empty
 
 
 class MockModel:
@@ -14,34 +14,34 @@ class MockOBBject:
         self.results = results
 
 
-class TestToDicts:
+class TestToList:
     def test_none_result(self):
-        assert _to_dicts(None) == []
+        assert to_list(None) == []
 
     def test_none_results(self):
         obj = MockOBBject(results=None)
-        assert _to_dicts(obj) == []
+        assert to_list(obj) == []
 
     def test_list_results(self):
         obj = MockOBBject(results=[
             MockModel({"a": 1}),
             MockModel({"b": 2}),
         ])
-        result = _to_dicts(obj)
+        result = to_list(obj)
         assert len(result) == 2
         assert result[0] == {"a": 1}
 
     def test_single_result(self):
         obj = MockOBBject(results=MockModel({"x": 42}))
-        result = _to_dicts(obj)
+        result = to_list(obj)
         assert result == [{"x": 42}]
 
 
 class TestFirstOrEmpty:
     def test_empty(self):
-        assert _first_or_empty(None) == {}
+        assert first_or_empty(None) == {}
 
     def test_with_data(self):
         obj = MockOBBject(results=[MockModel({"price": 150.0})])
-        result = _first_or_empty(obj)
+        result = first_or_empty(obj)
         assert result == {"price": 150.0}