Have a _sdl2 mode where make_surface is never called whith alpha=True

[cbdj]

Is your feature request related to a problem? Please describe.
When using pygame-menu(-ce) in sdl2 mode, we get exceptions each time make_surface is called with alpha=True :

No video mode has been set
File "C:\Users*****\AppData\Local\Programs\Python\Python311\Lib\site-packages\pygame_menu\utils.py", line 434, in make_surface
surface = pygame.Surface.convert_alpha(surface)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Describe the solution you'd like
convert_alpha should no more be called as it no longer provide much improvement in normal mode, and breaks sdl2 mode.

Describe alternatives you've considered
Or there should be a sdl2 mode...