boards: st: nucleo_wba52cg: Remove the support of Nucleo WBA52CG board

Remove the support of the Nucleo WBA52CG board since it is NRND
(Not Recommended for New Design) and it is not supported anymore
in the STM32CubeWBA from version 1.1.0 (July 2023).

Signed-off-by: Nidhal BEN OTHMEN <nidhal.benothmen@st.com>

Author: benothmn-st