tests: Bluetooth: Audio: Add -RealEncryption=1 to all bsim tests

Several BSIM tests did not enable -RealEncryption=1.
Since everything in LE Audio effectively requires encryption,
we should enable it, as we have seen a few tests passing before
that shouldn't, because they didn't set -RealEncryption=1.

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