Allow XamUserReadProfileSettings to use xuid to define profile

src/xenia/kernel/kernel_state.h

@@ -108,14 +108,31 @@ class KernelState {
   uint8_t GetConnectedUsers() const;
   void UpdateUsedUserProfiles();
 
-  bool IsUserSignedIn(uint8_t index) const {
+  bool IsUserSignedIn(uint32_t index) const {
     return user_profiles_.find(index) != user_profiles_.cend();
   }
 
-  xam::UserProfile* user_profile(uint8_t index) const {
+  bool IsUserSignedIn(uint64_t xuid) const {
+    return user_profile(xuid) != nullptr;
+  }
+
+  xam::UserProfile* user_profile(uint32_t index) const {
+    if (!IsUserSignedIn(index)) {
+      return nullptr;
+    }
+
     return user_profiles_.at(index).get();
   }
 
+  xam::UserProfile* user_profile(uint64_t xuid) const {
+    for (const auto& [key, value] : user_profiles_) {
+      if (value->xuid() == xuid) {
+        return user_profiles_.at(key).get();
+      }
+    }
+    return nullptr;
+  }
+
   // Access must be guarded by the global critical region.
   util::ObjectTable* object_table() { return &object_table_; }