fix pulseaudio cardname audio_setup.sh generation

[mcdonc]

• Description of what the PR does, such as fixes # {issue number}

PR against the feature/pulseaudio branch; single ticks prevent cardname interpolation. See https://community.mycroft.ai/t/picroft-headphones-no-output-sound/10852/15

• Description of how to validate or test this PR

Choose a custom USB sink and source. View the audio_setup.sh before this PR (contains ${card_name} literally), after contains the interpolated card name.

• Whether you have signed a CLA (Contributor Licensing Agreement)

No.