Add setting/experiment for small battery devices to have
all forced app standby enabled except for when the device
is charging.

Reverting the revert of this CL. The only change is to use
EXTRA_PLUGGED instead of EXTRA_STATUS in detecting charging
state. Verified that this passes CTS test for battery saver.

Bug: 69259147
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/ForceAppStandbyTrackerTest.java
Test: atest CtsBatterySavingTestCases
Change-Id: I4f3ffc0c865a1a3a035b6d9d6838b5056b666eb9
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index 37b3180..1482baf 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -213,6 +213,7 @@
                     Settings.Global.FANCY_IME_ANIMATIONS,
                     Settings.Global.FORCE_ALLOW_ON_EXTERNAL,
                     Settings.Global.FORCED_APP_STANDBY_ENABLED,
+                    Settings.Global.FORCED_APP_STANDBY_FOR_SMALL_BATTERY_ENABLED,
                     Settings.Global.FSTRIM_MANDATORY_INTERVAL,
                     Settings.Global.GLOBAL_HTTP_PROXY_EXCLUSION_LIST,
                     Settings.Global.GLOBAL_HTTP_PROXY_HOST,