Fix import when trace is missing from opentelemetry (#99)

Author: pquentin

elasticsearch_serverless/_otel.py

@@ -28,7 +28,7 @@
     from opentelemetry import trace
 
     _tracer: trace.Tracer | None = trace.get_tracer("elasticsearch-api")
-except ModuleNotFoundError:
+except ImportError:
     _tracer = None
 
 from elastic_transport import OpenTelemetrySpan