Add flag to exclude policy exempt field trials when listing expired ones

Bug: None
Change-Id: I07bc9f3ad1172bcdaf205937fb518ec295c022bf
No-Try: True
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/346420
Commit-Queue: Emil Lundmark <lndmrk@webrtc.org>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#42019}
diff --git a/experiments/field_trials.py b/experiments/field_trials.py
index 8274c03..4bf2e62 100755
--- a/experiments/field_trials.py
+++ b/experiments/field_trials.py
@@ -1027,7 +1027,9 @@
 def cmd_expired(args: argparse.Namespace) -> None:
     today = todays_date()
     diff = datetime.timedelta(days=args.in_days)
-    expired = expired_field_trials(today + diff)
+    expired = expired_field_trials(
+        today + diff,
+        REGISTERED_FIELD_TRIALS if args.exempt else ACTIVE_FIELD_TRIALS)
 
     if len(expired) <= 0:
         return
@@ -1073,6 +1075,11 @@
         any field trials has expired, ignoring the --in-days argument.
         ''')
     parser_expired.add_argument(
+        '--exempt',
+        default=True,
+        action=argparse.BooleanOptionalAction,
+        help='whether to include policy exempt field trials')
+    parser_expired.add_argument(
         '--in-days',
         default=0,
         type=int,