Include a developer option sliding flag to toggle the different amount of apps to show

Bug: 299294792
Test: Verified SearchTransitionController didn't regress by turning off BACKGROUND_DRAWABLES flag.
Flag: ACONFIG com.android.launcher3.Flags.enable_private_space DEVELOPMENT
Change-Id: I78ee3a9dbc2d60f1b7acaa5834a8c656217a07d8
diff --git a/src/com/android/launcher3/LauncherPrefs.kt b/src/com/android/launcher3/LauncherPrefs.kt
index a05b0f5..78056e6 100644
--- a/src/com/android/launcher3/LauncherPrefs.kt
+++ b/src/com/android/launcher3/LauncherPrefs.kt
@@ -364,6 +364,13 @@
                         EncryptionType.MOVE_TO_DEVICE_PROTECTED
                 )
         @JvmField
+        val PRIVATE_SPACE_APPS =
+                nonRestorableItem(
+                        "pref_private_space_apps",
+                        0,
+                        EncryptionType.MOVE_TO_DEVICE_PROTECTED
+                )
+        @JvmField
         val THEMED_ICONS =
             backedUpItem(Themes.KEY_THEMED_ICONS, false, EncryptionType.MOVE_TO_DEVICE_PROTECTED)
         @JvmField val PROMISE_ICON_IDS = backedUpItem(InstallSessionHelper.PROMISE_ICON_IDS, "")