Add keys to all Preferences on the Managed device info page

In order to be able to hide the page from search results, all Preferences
(and PreferenceCategories) must have android:keys.

Bug: 62285529
Test: The Settings framework will have a test that ensure each Preference
Test: has a key from O-DR onward

Change-Id: I1e41ce6f8b9f90155ef92354b9268e9e720e1e73
diff --git a/res/xml/enterprise_privacy_settings.xml b/res/xml/enterprise_privacy_settings.xml
index 2d07fa2..13f7b8e 100644
--- a/res/xml/enterprise_privacy_settings.xml
+++ b/res/xml/enterprise_privacy_settings.xml
@@ -20,19 +20,23 @@
                   android:title="@string/enterprise_privacy_settings">
 
     <!-- Header -->
-    <Preference
-            android:icon="@drawable/ic_info_outline_24dp"
-            android:summary="@string/enterprise_privacy_header"
-            android:selectable="false"/>
+    <Preference android:key="enterprise_privacy_header"
+                android:icon="@drawable/ic_info_outline_24dp"
+                android:summary="@string/enterprise_privacy_header"
+                android:selectable="false"/>
 
-    <PreferenceCategory android:title="@string/enterprise_privacy_exposure_category"
+    <PreferenceCategory android:key="exposure_category"
+                        android:title="@string/enterprise_privacy_exposure_category"
                         android:contentDescription="@string/enterprise_privacy_exposure_category">
-        <Preference android:layout_height="wrap_content"
+        <Preference android:key="enterprise_privacy_enterprise_data"
+                    android:layout_height="wrap_content"
                     android:title="@string/enterprise_privacy_enterprise_data"
                     android:selectable="false"/>
-        <Preference android:title="@string/enterprise_privacy_installed_packages"
+        <Preference android:key="enterprise_privacy_installed_packages"
+                    android:title="@string/enterprise_privacy_installed_packages"
                     android:selectable="false"/>
-        <Preference android:title="@string/enterprise_privacy_usage_stats"
+        <Preference android:key="enterprise_privacy_usage_stats"
+                    android:title="@string/enterprise_privacy_usage_stats"
                     android:selectable="false"/>
         <Preference android:key="network_logs"
                     android:title="@string/enterprise_privacy_network_logs"
@@ -78,10 +82,13 @@
                     android:selectable="false"/>
     </PreferenceCategory>
 
-    <PreferenceCategory android:title="@string/enterprise_privacy_device_access_category">
-        <Preference android:title="@string/enterprise_privacy_lock_device"
+    <PreferenceCategory android:key="device_access_category"
+                        android:title="@string/enterprise_privacy_device_access_category">
+        <Preference android:key="enterprise_privacy_lock_device"
+                    android:title="@string/enterprise_privacy_lock_device"
                     android:selectable="false"/>
-        <Preference android:title="@string/enterprise_privacy_wipe_device"
+        <Preference android:key="enterprise_privacy_wipe_device"
+                    android:title="@string/enterprise_privacy_wipe_device"
                     android:selectable="false"/>
         <Preference android:key="failed_password_wipe_current_user"
                     android:title="@string/enterprise_privacy_failed_password_wipe_device"