Bluetooth: Host: Fix GATT Store on Write

When CCC or CF store on write is disabled and the other one is enabled,
leading to the delayed store being enabled. This cause the value of the
corresponding `n` selected option to not be stored at all.

To fix this, the checks to know if we need to store the CCC or the CF,
happening at the disconnection, are now ensuring that the CCC or the CF
are stored even if the one of them does not enable store on write.

Signed-off-by: Théo Battrel <theo.battrel@nordicsemi.no>