pulse-server: update all params only after enumeration complete

For params that don't emit change events, the param enumeration does not start core sync, and its enumeration may be incomplete if a previous core sync completes first.

Fix by always starting a core sync if we are updating params.

This fixes dev_info.active_port being sporadically SPA_ID_INVALID if there is event pressure, which causes do_set_volume randomly set the volume on the node instead of setting it on the device. This can be triggered e.g. by shaking the volume slider in Pavucontrol with mouse.