[Enhancement] BIOS checker for Switch is ambiguous

[Mellified]

Switch BIOS files (firmware and keys) must be installed for both Yuzu and Ryujinx in different ways and locations. The BIOS checker function of EmuDeck simply references "Switch" - not the individual emulators. This is confusing, since the user could potentially have one or the other correctly configured - but not both.

Suggest splitting this up so that each emulator's status is checked and displayed separately. It would be useful to mark Ryujinx as yellow - as opposed to green or red - if the Switch keys are installed but the in-emulator firmware file installation has not been completed.