[pulseaudio] Fix sink-input configuration and other (#11272) (#11276)

[pulseaudio] Fix sink-input configuration and other (#11272) (#11276)

* [pulseaudio] Fix sink-input configuration  and other small improvements (#11272)

The binding requires a parameter to activate the parsing of sink-input entries on the pulseaudio server. This patch :
- document this behaviour
- fix the parsing of these parameters if a configuration file is used (the old method of casting launched a class cast exception)

Other small improvements :
- Force a refresh/new parsing when the configuration changes
- Fix scheduled disconnection : if a sound is played during the grace period, the scheduled disconnection is postponed, not added to the last
- add a possibility to never disconnect the audio sink (in order to have a lower latency when playing sound)
Closes #11272

Signed-off-by: Gwendal Roulleau <gwendal.roulleau@gmail.com>
* Small fixes after proofreading

Signed-off-by: Gwendal Roulleau <gwendal.roulleau@gmail.com>
Co-authored-by: Gwendal Roulleau <gwendal.roulleau@gmail.com>