Making 2 flags read only since they are used on backup and restore

The flags are narrow_grid_restore and grid_migration_fix.

Flag: ACONFIG enable_grid_migration_fix enabled
Flag: ACONFIG enable_narrow_grid_restore enabled
Bug: 325286145
Bug: 325285743
Test: BackupAndRestoreDBSelectionTest.kt
Test: GridMigrationTest.kt
Change-Id: Ia6a439553c3c5098115144eae532342ce73be4f2
diff --git a/aconfig/launcher.aconfig b/aconfig/launcher.aconfig
index 20c5248..4de1c96 100644
--- a/aconfig/launcher.aconfig
+++ b/aconfig/launcher.aconfig
@@ -188,19 +188,21 @@
 }
 
 flag {
-    name: "grid_migration_fix"
+    name: "enable_grid_migration_fix"
     namespace: "launcher"
     description: "Keep items in place when migrating to a bigger grid"
     bug: "325286145"
+    is_fixed_read_only: true
     metadata {
       purpose: PURPOSE_BUGFIX
     }
 }
 
 flag {
-    name: "narrow_grid_restore"
+    name: "enable_narrow_grid_restore"
     namespace: "launcher"
     description: "Using only the most recent workspace when restoring to avoid confusion."
+    is_fixed_read_only: true
     bug: "325285743"
     metadata {
       purpose: PURPOSE_BUGFIX