improve metrics.py

Signed-off-by: justwph <2732352+wph95@users.noreply.github.com>

Author: wph95

python/ray/util/metrics.py

@@ -198,7 +198,7 @@ def __init__(
         if self._discard_metric:
             self._metric = None
         else:
-            if os.environ.get("RAY_enable_open_telemetry") == "1":
+            if os.environ.get("RAY_enable_open_telemetry") == "true":
                 """
                 For the new opentelemetry implementation, we'll correctly use Counter
                 rather than Sum.