[easy] FORGE_DISABLE_METRICS also disables Tracer (meta-pytorch#366)

* <Replace this line with a title. Use 1 line only, 67 chars or less>

Summary:

Test Plan:

Reviewers:

Subscribers:

Tasks:

Tags:

* fix logic

* add lower

---------

Co-authored-by: Felipe Mello <[email protected]>

Author: felipemello1

src/forge/observability/perf_tracker.py

@@ -15,7 +15,11 @@
 
 import torch
 
-from forge.env_constants import DISABLE_PERF_METRICS, METRIC_TIMER_USES_GPU
+from forge.env_constants import (
+    DISABLE_PERF_METRICS,
+    FORGE_DISABLE_METRICS,
+    METRIC_TIMER_USES_GPU,
+)
 from forge.observability.metrics import record_metric, Reduce
 
 logger = logging.getLogger(__name__)
@@ -108,7 +112,10 @@ def __init__(
         self.prefix = prefix
         self.track_memory = track_memory
         self.time_with_gpu = timer == "gpu"
-        self._disable = os.getenv(DISABLE_PERF_METRICS, "false") == "true"
+        self._disable = (
+            os.getenv(DISABLE_PERF_METRICS, "false").lower() == "true"
+            or os.getenv(FORGE_DISABLE_METRICS, "false").lower() == "true"
+        )
         self._active = False
 
         # Timing state