Fix an assumption that UserHandle.myUserId() always returns the main

user.

In some cases, e.g. in Private Space Storage Info fragment it returns
the Private profile id and this was leading to a crash, see b/378471943.

Bug: 378471943
Test: Manually and presubmit
Flag: com.android.settings.flags.utils_return_user_handle_for_current_user_id
Change-Id: I5f7bedc66ebcac8b0ae265b7189dd1821edb3cd7

aconfig/settings_flag_declarations.aconfig

@@ -70,3 +70,13 @@ flag {
   description: "Flag for catalyst service"
   bug: "323791114"
 }
+
+flag {
+  name: "utils_return_user_handle_for_current_user_id"
+  namespace: "profile_experiences"
+  description: "Don't ignore the current user id when checking for existing profiles."
+  bug: "378471943"
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+}