Make StringView::Empty const to fix issues with user accidentally changing the value.

Source/Engine/Core/Types/StringView.cpp

@@ -9,7 +9,7 @@ StringView StringBuilder::ToStringView() const
     return StringView(_data.Get(), _data.Count());
 }
 
-StringView StringView::Empty;
+const StringView StringView::Empty;
 
 StringView::StringView(const String& str)
     : StringViewBase<Char>(str.Get(), str.Length())

Source/Engine/Core/Types/StringView.h

@@ -219,7 +219,7 @@ public:
     /// <summary>
     /// Instance of the empty string.
     /// </summary>
-    static StringView Empty;
+    static const StringView Empty;
 
 public:
     /// <summary>