[Partial Screen Sharing] Migrate task switcher flag to aconfig

In order to launch the feature in V, we will have to use the
new flagging system (aconfig).

Flag: ACONFIG com.android.systemui.pss_task_switcher DISABLED
Test: MediaProjectionTaskSwitcherCoreStartableTest.kt
Test: Manual
Bug: 317208379
Fixes: 288868056
Change-Id: I8860987c5188d34178dc27b476907bd6bbf8a6d4
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index d8d3f87..97ff379 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -175,6 +175,13 @@
 }
 
 flag {
+   name: "pss_task_switcher"
+   namespace: "systemui"
+   description: "Enable the task switcher feature for partial screen sharing"
+   bug: "317208379"
+}
+
+flag {
    name: "rest_to_unlock"
    namespace: "systemui"
    description: "Require prolonged touch for fingerprint authentication"