Fix OTA info persistence logic

Code to persist OTA info was accidentally removed by a previous CL.
Add it back.

Bug: 73505100
Test: gts-tradefed run gts-dev --module GtsGmscoreHostTestCases --test com.google.android.gts.devicepolicy.DeviceOwnerTest#testPendingSystemUpdate
Change-Id: I9eba522641fd8f95cd6af32431498c2c8ac5ff0e

services/devicepolicy/java/com/android/server/devicepolicy/Owners.java

@@ -723,6 +723,11 @@ class Owners {
                 mSystemUpdatePolicy.saveToXml(out);
                 out.endTag(null, TAG_SYSTEM_UPDATE_POLICY);
             }
+
+            if (mSystemUpdateInfo != null) {
+                mSystemUpdateInfo.writeToXml(out, TAG_PENDING_OTA_INFO);
+            }
+
             if (mSystemUpdateFreezeStart != null || mSystemUpdateFreezeEnd != null) {
                 out.startTag(null, TAG_FREEZE_PERIOD_RECORD);
                 if (mSystemUpdateFreezeStart != null) {