[Feature Request] Add support for Disc label handling for m3u/ Disc Control UI

[retropieuser]

At the moment BlueMSX does not pass or use the retro_get_image_label_t function that is commonly used in cores such as Swanstation or Flycast.

As a result you don't see what floppy disks are loaded in the UI:-

Here is Swanstation:-

Could this be implemented please?

[2play]

confirm the core shows blank index

[2play]

@retropieuser i have tried different approaches on a fork to apply this blank index bss the bluemsx libretro.c but with no luck so far
I let the devs here to hopefully resolve it

[retropieuser]

I'm afraid the attempt to fix this 672b19cd5f7a4ccdc9740123209ea98b54a2767e seems to just cause a crash when trying to load any m3u file now. .dsk images work ok

[2play]

I'm afraid the attempt to fix this 672b19cd5f7a4ccdc9740123209ea98b54a2767e seems to just cause a crash when trying to load any m3u file now. .dsk images work ok

confirm same

[Larsvb0]

Same since 1.21.0 on Apple tv

libretro/RetroArch#17849