Give a warning whenever span attribute was truncated

Is your feature request related to a problem?

I'd like my app's users to be informed whenever their span is truncated. Currently there's no warning being logged in Otel.

opentelemetry/attributes/__init__.py

Describe the solution you'd like

I'd like this method to log a warning whenever span attribute is truncated due to limitation:

def _clean_attribute_value(
    value: types.AttributeValue, limit: Optional[int]
) -> Optional[types.AttributeValue]:
    if value is None:
        return None

    if isinstance(value, bytes):
        try:
            value = value.decode()
        except UnicodeDecodeError:
            _logger.warning("Byte attribute could not be decoded.")
            return None

    if limit is not None and isinstance(value, str):
        value = value[:limit]
    return value

Describe alternatives you've considered

No response

Additional Context

No response

Would you like to implement a fix?

None

Start in opentelemetry/attributes/init.py at _clean_attribute_value and inspect how the existing byte-decoding warning is handled. Add a warning for string values truncated by the limit, then verify that truncation emits the warning while unaffected values do not.