service: Resolve trivially avoidable copies (#5237)

* am/am: Avoid redundant copy in GetProgramInfoFromCia()

We can just use a reference to the title metadata. Avoids copying
several data entries and std::vector instances that don't need to be
copied.

* hle/service: Avoid redundant copying of std::string

GetUserPath() returns the path as a reference, so we can make use of
said reference to avoid making copies.

src/core/hle/service/am/am.cpp

@@ -1222,7 +1222,7 @@ void Module::Interface::GetProgramInfoFromCia(Kernel::HLERequestContext& ctx) {
         return;
     }
 
-    FileSys::TitleMetadata tmd = container.GetTitleMetadata();
+    const FileSys::TitleMetadata& tmd = container.GetTitleMetadata();
     TitleInfo title_info = {};
     container.Print();