fix: make starter projects auto refactor not remove selected output (#8400)

* Fixed bug where starter projects were refactored incorrectly

* fix: improve handling of selected outputs in custom component template builder

- Added checks to ensure selected output is valid before attempting to set its state.
- Enhanced code readability with comments explaining the logic for selecting outputs.

* Set selected output as the previous selected output

* Update base.py

---------

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>
Co-authored-by: Edwin Jose <edwin.jose@datastax.com>

src/backend/tests/unit/test_schema.py

@@ -127,11 +127,6 @@ class TestOutput:
         output_obj.add_types(["str", "int"])
         assert output_obj.types == ["str", "int"]
 
-    def test_output_set_selected(self):
-        output_obj = Output(name="test_output", types=["str", "int"])
-        output_obj.set_selected()
-        assert output_obj.selected == "str"
-
     def test_output_to_dict(self):
         output_obj = Output(name="test_output")
         assert output_obj.to_dict() == {