boards: st: nucleo_wb0: Remove arduino_gpio compatibility declaration

gpio_basic_api test configuration drivers.gpio.2pin_arduino expects
arduino pins D2 and D3 to be available but they aren't declared in
arduino connectors for this board as not available by default.

Remove arduino_gpio compatibility declaration for now.

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>