Bluetooth: Test `bt_uuid_to_str`
Bluetooth: Test `bt_uuid_to_str`

Add missing unit tests for `bt_uuid_to_str`.

Signed-off-by: Aleksander Wasaznik <c0d989573cb73e7c43339e7aaab9bc0cb8ebe8c5@nordicsemi.no>

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