fix: ensure the start_ns of a function url inferred span is an int

Author: florentinl

datadog_lambda/tracing.py

@@ -859,7 +859,7 @@ def create_inferred_span_from_lambda_function_url_event(event, context):
     InferredSpanInfo.set_tags(tags, tag_source="self", synchronicity="sync")
     if span:
         span.set_tags(tags)
-        span.start_ns = int(request_time_epoch) * 1e6
+        span.start_ns = int(request_time_epoch * 1e6)
     return span