board/shields: x-nucleo-iks01a3: (FIX) use INT2 for LSM6DSO DRDY

On LSM6DSO sensor the INT1 pin is used for both generating the drdy
interrupt and for switching to I3C hotjoin mode just after reset if
it is at logical '1' level. If you reset the x_nucleo_shield3 board
the LSM6DSO enter in hot join, as INT1 '1' level is preserved by
the level shifter.

This commit switch to INT2 to generate DRDY interrupt, so that INT1
always remain to logical '0' level.

Fixes: #20933

Signed-off-by: Armando Visconti <armando.visconti@st.com>