[ios] Add missing label to the about:policy handler.

BUG=1082705

Change-Id: I8d26b2b81b4d5e50f7f7d5504ae978997d68a3c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2202144Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#768870}

ios/chrome/browser/ui/webui/policy/policy_ui.mm

@@ -59,6 +59,7 @@ web::WebUIIOSDataSource* CreatePolicyUIHtmlSource() {
       {"labelStatus", IDS_POLICY_LABEL_STATUS},
       {"labelTimeSinceLastRefresh", IDS_POLICY_LABEL_TIME_SINCE_LAST_REFRESH},
       {"labelUsername", IDS_POLICY_LABEL_USERNAME},
+      {"labelVersion", IDS_POLICY_LABEL_VERSION},
       {"noPoliciesSet", IDS_POLICY_NO_POLICIES_SET},
       {"offHoursActive", IDS_POLICY_OFFHOURS_ACTIVE},
       {"offHoursNotActive", IDS_POLICY_OFFHOURS_NOT_ACTIVE},