Simplified ExtUI language selection (#15359)

Marlin/Configuration_adv.h

Marlin/src/lcd/dogm/ultralcd_DOGM.h

...tdi_eve_lib/extended/unicode/western_char_set_bitmap_31.h

...n/src/lcd/extensible_ui/lib/lulzbot/language/language.cpp

Marlin/src/lcd/extensible_ui/lib/lulzbot/language/language.h

.../src/lcd/extensible_ui/lib/lulzbot/language/language_de.h

.../src/lcd/extensible_ui/lib/lulzbot/language/language_en.h

.../src/lcd/extensible_ui/lib/lulzbot/language/language_fr.h

...src/lcd/extensible_ui/lib/lulzbot/screens/boot_screen.cpp

...c/lcd/extensible_ui/lib/lulzbot/screens/language_menu.cpp

Marlin/src/lcd/extensible_ui/lib/lulzbot/screens/screens.cpp

Marlin/src/lcd/extensible_ui/lib/lulzbot/screens/screens.h

..._flashdrive/lib-uhs3/UHS_host/UHS_BULK_STORAGE/UHS_SCSI.h

Marlin/src/sd/usb_flashdrive/lib-uhs3/UHS_host/UHS_USB_IDs.h

Marlin/src/sd/usb_flashdrive/lib-uhs3/UHS_host/UHS_macros.h

...c/sd/usb_flashdrive/lib-uhs3/UHS_host/UHS_printf_HELPER.h

config/default/Configuration_adv.h

config/examples/3DFabXYZ/Migbot/Configuration_adv.h

config/examples/ADIMLab/Gantry v1/Configuration_adv.h

config/examples/ADIMLab/Gantry v2/Configuration_adv.h