Add separate system property to control user toggle

This allows to ship the developer toggle independent of the settings
toggle. This also allows other parts of the system to query whether the
settings toggle is available.

Bug: 244290023
Change-Id: I1a6b6457974a7107711cd4f7d990a6fe61bf340f

src/com/android/settings/security/MemtagHelper.java

@@ -46,7 +46,7 @@ public class MemtagHelper {
         if (MemtagHelper.isForcedOff()) {
             return BasePreferenceController.DISABLED_DEPENDENT_SETTING;
         }
-        return SystemProperties.getBoolean("ro.arm64.memtag.bootctl_supported", false)
+        return SystemProperties.getBoolean("ro.arm64.memtag.bootctl_settings_toggle", false)
                 ? BasePreferenceController.AVAILABLE
                 : BasePreferenceController.UNSUPPORTED_ON_DEVICE;
     }