UICommon/ResourcePack: Mark ResourcePack's operator== as const

Source/Core/UICommon/ResourcePack/ResourcePack.cpp

@@ -320,7 +320,7 @@ bool ResourcePack::Uninstall(const std::string& path)
   return true;
 }
 
-bool ResourcePack::operator==(const ResourcePack& pack)
+bool ResourcePack::operator==(const ResourcePack& pack) const
 {
   return pack.GetPath() == m_path;
 }

Source/Core/UICommon/ResourcePack/ResourcePack.h

@@ -30,7 +30,7 @@ public:
   bool Install(const std::string& path);
   bool Uninstall(const std::string& path);
 
-  bool operator==(const ResourcePack& pack);
+  bool operator==(const ResourcePack& pack) const;
 
 private:
   bool m_valid = true;