message: opentelemetry: fix event source locations
  Fixes:
  ## Motivation
  Properly attach event's source locations.
  ## Solution
  Append the locations to events' attributes instead of span's
  attributes.
diff: @@ -580,8 +580,6 @@ where
  }
  if self.event_location {
  - let builder_attrs = builder.attributes.get_or_insert(Vec::new());
  -
  #[cfg(not(feature = "tracing-log"))]
  let normalized_meta: Option<tracing_core::Metadata<'_>> = None;
  let (file, module) = match &normalized_meta {
  @@ -596,13 +594,19 @@ where
  };
  if let Some(file) = file {
  - builder_attrs.push(KeyValue::new("code.filepath", file));
  + otel_event
  + .attributes
  + .push(KeyValue::new("code.filepath", file));
  }
  if let Some(module) = module {
  - builder_attrs.push(KeyValue::new("code.namespace", module));
  + otel_event
  + .attributes
  + .push(KeyValue::new("code.namespace", module));
  }
  if let Some(line) = meta.line() {
  - builder_attrs.push(KeyValue::new("code.lineno", line as i64));
  + otel_event
  + .attributes
  + .push(KeyValue::new("code.lineno", line as i64));
  }
  }
  