Bluetooth: ISO: Pointer check in bt_iso_connected was incorrect
Bluetooth: ISO: Pointer check in bt_iso_connected was incorrect

Instead of checking `if (iso == NULL)` it simply checked
`if (iso)` which is the opposite of what it should have done.

This completely blocks iso from connecting channels.

Signed-off-by: Emil Gydesen <a20314356615223738233ab4c4eb1cd8cd4146fa@nordicsemi.no>

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