Remove sleep_timeout setting from backup

It is not user-configurable.

Bug: 79779285
Test: atest SettingsBackupTest
Test: # w/ LocalTransport
      adb shell settings put secure sleep_timeout 5000
      adb shell bmgr backupnow com.android.providers.settings
      adb shell settings put secure sleep_timeout 3000
      adb shell bmgr restore 1 com.android.providers.settings
      adb shell settings get secure sleep_timeout => ensure 3000

Change-Id: I68bf2f91cc3d4c00463468a6abaef3b64d5c10b9
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index 14c641a..8c16d83 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -595,6 +595,7 @@
                  Settings.Secure.SHOW_NOTE_ABOUT_NOTIFICATION_HIDING, // candidate?
                  Settings.Secure.SHOW_ROTATION_SUGGESTIONS,
                  Settings.Secure.SKIP_FIRST_USE_HINTS, // candidate?
+                 Settings.Secure.SLEEP_TIMEOUT,
                  Settings.Secure.SMS_DEFAULT_APPLICATION,
                  Settings.Secure.THEME_MODE,
                  Settings.Secure.TRUST_AGENTS_INITIALIZED,