Add flag for recoverability_detection

This flags are causing merge conflicts while cherry-picking them in aosp/2921425. So adding them separately from it.

Bug: 291135724
Test: NA
Change-Id: I555f5edb76ddc107c071b8b4c6909ef54ecf46eb
Merged-In: I880256bbcba1126b8d6657dfc77d5f6a0f11e76a

core/java/android/content/pm/flags.aconfig

@@ -115,3 +115,11 @@ flag {
     description: "Feature flag to fix duplicated PackageManager flag values"
     bug: "314815969"
 }
+
+flag {
+    name: "recoverability_detection"
+    namespace: "package_manager_service"
+    description: "Feature flag to enable recoverability detection feature. It includes GMS core rollback and improvements to rescue party."
+    bug: "291135724"
+    is_fixed_read_only: true
+}