Add kReleaseLtsTag to kKnownSettings

Add missing entry to kKnownSettings.

Bug: chromium:1116336
Change-Id: Ib00bc2f60b1d27851d1675e32f259c767da11ad9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2353261Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Victor-Gabriel Savu <vsavu@google.com>
Cr-Commit-Position: refs/heads/master@{#798142}

chrome/browser/chromeos/settings/device_settings_provider.cc

@@ -114,6 +114,7 @@ const char* const kKnownSettings[] = {
     kRebootOnShutdown,
     kReleaseChannel,
     kReleaseChannelDelegated,
+    kReleaseLtsTag,
     kDeviceChannelDowngradeBehavior,
     kReportDeviceActivityTimes,
     kReportDeviceBluetoothInfo,