Policy Ui sends correct translations for risk tags.

Send localized group names to frontend and reuse some strings from
the old WebUi.
(Prerequisite for CL 1371073003)

BUG=134849

Review URL: https://codereview.chromium.org/1395073002

Cr-Original-Commit-Position: refs/heads/master@{#362997}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 07c5e062f2ea6ef0e3b5844f1a11ecb4df4d41f6

ios/grit_whitelist.txt

@@ -464,6 +464,13 @@ IDS_PLATFORM_LABEL
 IDS_PLUGIN_CONFIRM_INSTALL_DIALOG_ACCEPT_BUTTON
 IDS_PLUGIN_CONFIRM_INSTALL_DIALOG_TITLE
 IDS_PLUGIN_NOT_SUPPORTED
+IDS_POLICY_RISK_TAG_ADMIN_SHARING
+IDS_POLICY_RISK_TAG_FILTERING
+IDS_POLICY_RISK_TAG_FULL_ADMIN_ACCESS
+IDS_POLICY_RISK_TAG_GOOGLE_SHARING
+IDS_POLICY_RISK_TAG_LOCAL_DATA_ACCESS
+IDS_POLICY_RISK_TAG_SYSTEM_SECURITY
+IDS_POLICY_RISK_TAG_WEBSITE_SHARING
 IDS_PREFERENCES_CORRUPT_ERROR
 IDS_PREFERENCES_UNREADABLE_ERROR
 IDS_PRINT