Function parse_extra_tracing_attributes 

fn parse_extra_tracing_attributes(input: &str) -> Vec<KeyValue>

Parse a comma-separated list of key=value pairs into OpenTelemetry KeyValue attributes.

• Splits by comma to get pairs.
• Each pair must contain exactly one =.
• Trims whitespace around key and value.
• Ignores invalid pairs but logs a warning.
• Returns an empty vec for empty or unset input.