Regression in Markdown.code_theme when using MarkdownCodeTheme enum

[ndonkoHenri]

A custom theme works great although the only issue I faced was setting code_theme with ft.MarkdownCodeTheme.ATOM_ONE_DARK or any other value but only using ft.MarkdownTheme class the error it throws is:

Code

import flet as ft

data = """
```python
class MyClass(object):
    def __init__(self):
        pass
        
    def greet(self):
        print("Hello World")
    ```
"""
def main(page: ft.Page):
    page.add(
        ft.Markdown(
            value=data,
            code_theme=ft.MarkdownCodeTheme.ATOM_ONE_DARK,
            extension_set=ft.MarkdownExtensionSet.GITHUB_WEB,
        )
    )
ft.app(main)

Error

(.venv) PS D:\CodingFolder\myCodingFilesPy\Flet\leraning> flet run .\theme\ --web                                                                                                                        
http://127.0.0.1:54949
D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\websockets\legacy\server.py:1185: DeprecationWarning: remove second argument of ws_handler
  warnings.warn("remove second argument of ws_handler", DeprecationWarning)
Unhandled error processing page session 49apGh5JlJ9Wkk0V: Traceback (most recent call last):
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet_web\fastapi\flet_app.py", line 141, in __on_session_created
    await asyncio.get_running_loop().run_in_executor(
  File "C:\ProgramData\anaconda3\Lib\concurrent\futures\thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\theme\main.py", line 12, in main
    page.add(
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\page.py", line 737, in add
    r = self.__update(self)
        ^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\page.py", line 835, in __update
    commands, added_controls, removed_controls = self.__prepare_update(*controls)
                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\page.py", line 851, in __prepare_update
    control.build_update_commands(
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 497, in build_update_commands
    innerCmds = ctrl._build_add_commands(
                ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 562, in _build_add_commands
    childCmd = control._build_add_commands(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 551, in _build_add_commands
    command = self._build_command(False)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 578, in _build_command
    self.before_update()
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\markdown.py", line 403, in before_update
    self._set_attr_json("codeTheme", self.__code_theme)
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 189, in _set_attr_json
    nv = self._convert_attr_json(
         ^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\control.py", line 197, in _convert_attr_json
    json.dumps(value, cls=EmbedJsonEncoder, separators=(",", ":"))
  File "C:\ProgramData\anaconda3\Lib\json\__init__.py", line 238, in dumps
    **kw).encode(obj)
          ^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\embed_json_encoder.py", line 59, in encode
    return super().encode(self._convert_enums(o))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\ProgramData\anaconda3\Lib\json\encoder.py", line 200, in encode
    chunks = self.iterencode(o, _one_shot=True)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\ProgramData\anaconda3\Lib\json\encoder.py", line 258, in iterencode
    return _iterencode(o, 0)
           ^^^^^^^^^^^^^^^^^
  File "D:\CodingFolder\myCodingFilesPy\Flet\leraning\.venv\Lib\site-packages\flet\core\embed_json_encoder.py", line 49, in default
    obj_as_dict = self._convert_enums(obj.__dict__)
                                      ^^^^^^^^^^^^
AttributeError: 'mappingproxy' object has no attribute '__dict__'

I think there's something wrong with ft.MarkdownTheme class because when I used "atom-one-dark" it worked. When I run the same code but with flet version, 0.24.1 it worked as expected. Kindly raise issue regarding this.

Originally posted by @tanmay-bhatgare in #4342 (comment)