Function parse_sonos_bool 

pub fn parse_sonos_bool(xml: &Element, child_name: &str) -> bool

Parse a Sonos UPnP boolean value from an XML response element.

Sonos devices return “0”/“1” for booleans, but Rust’s bool::parse() only handles “true”/“false”. This helper correctly parses “0”, “1”, “true”, “false”, and handles whitespace-padded variants.

Returns false if the child element is missing or empty.