nrf/bluetooth/ble_uart: Fix implicit declaration of function.
nrf/bluetooth/ble_uart: Fix implicit declaration of function.

mp_keyboard_interrupt() triggers a compiler error because the function is
implicitly declared.  This commit adds "py/runtime.h" to the includes.

Fixes issue #5732.

pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython