cpp: Fix C++ exception handling newlib dependency
cpp: Fix C++ exception handling newlib dependency

This commit makes C++ exception handling feature depend on the full
version of newlib (i.e. `CONFIG_NEWLIB_LIBC_NANO=n`).

The `nano.specs`, which selects the nano variant of newlib, libstdc++,
and libsupc++, does not support C++ exception handling because its
lib*c++ is compiled with `-fno-exceptions`.

For more details, refer to the issue #35972.

Signed-off-by: Stephanos Ioannidis <dc76e9f0c0006e8f919e0c515c66dbba3982f785@stephanos.io>

zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr