select_files fails when passed a var[str]

[bertbarabas]

Describe the bug
The following fails when
id = required_file.file_name_id
but works if
id=f"{required_file.file_name_id}"

        rx.foreach(
            rx.selected_files(id),
            file_to_upload,
        ),

exception is:

  File ".venv\Lib\site-packages\reflex\components\core\upload.py", line 90, in selected_files
    id_var = LiteralStringVar.create(id_)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".venv\Lib\site-packages\reflex\vars\sequence.py", line 1173, in create
    if REFLEX_VAR_OPENING_TAG in value:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".venv\Lib\site-packages\reflex\vars\base.py", line 1420, in __contains__
    raise VarTypeError(msg)
reflex.utils.exceptions.VarTypeError: 'in' operator not supported for Var types, use Var.contains() instead.
Happened while evaluating page 'console'

Expected behavior
No exception

Specifics (please complete the following information):

• Python Version: 3.12.4
• Reflex Version: 0.7.4
• OS: Window 11

[linear]

ENG-6410 select_files fails when passed a var[str]