cryptohome: UMA Metrics for VaultKeyset extension

Metrics for metadata on VaultKeysets still needs to be
tracked, extending for 6 months.

BUG=chromium:1317176
TEST=validate_format.py

Change-Id: If3c101b2a44b1db7829e10ed8b32a049b7c2c432
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3600635
Auto-Submit: Thomas Cedeno <thomascedeno@google.com>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Thomas Cedeno <thomascedeno@google.com>
Cr-Commit-Position: refs/heads/main@{#995242}
diff --git a/tools/metrics/histograms/metadata/cryptohome/histograms.xml b/tools/metrics/histograms/metadata/cryptohome/histograms.xml
index 7cf2093..e6f4508 100644
--- a/tools/metrics/histograms/metadata/cryptohome/histograms.xml
+++ b/tools/metrics/histograms/metadata/cryptohome/histograms.xml
@@ -607,7 +607,7 @@
 </histogram>
 
 <histogram name="Cryptohome.VaultKeysetMetric.{VaultKeysetMetric}"
-    units="count" expires_after="2022-06-01">
+    units="count" expires_after="2023-02-01">
   <owner>thomascedeno@google.com</owner>
   <owner>cros-hwsec+uma@chromium.org</owner>
   <summary>