pw_presubmit: Use 0 for bbid for led tasks

Change-Id: Ie51bef618d543609e355fbb04cdc65aaae7abd0c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/110475
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Ted Pudlik <tpudlik@google.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
diff --git a/pw_presubmit/py/pw_presubmit/presubmit.py b/pw_presubmit/py/pw_presubmit/presubmit.py
index c9f9a5d..dcfaf7b 100644
--- a/pw_presubmit/py/pw_presubmit/presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/presubmit.py
@@ -193,8 +193,14 @@
 
         project, bucket, builder = os.environ['BUILDBUCKET_NAME'].split(':')
 
+        bbid: int = 0
+        try:
+            bbid = int(os.environ['BUILDBUCKET_ID'])
+        except ValueError:
+            pass
+
         return LuciContext(
-            buildbucket_id=int(os.environ['BUILDBUCKET_ID']),
+            buildbucket_id=bbid,
             build_number=int(os.environ['BUILD_NUMBER']),
             project=project,
             bucket=bucket,