Move RADIX_TYPE enum into its own header (#25)

This change moves the RADIX_TYPE enum into its own header. This resolves a compilation error and reduces the dependency graph by allowing RadixToStringConverter to include just the enum header rather than the entire CalcEngine header.

Change verified by ensuring Calculator build locally.

src/Calculator/Converters/RadixToStringConverter.cpp

@@ -3,7 +3,7 @@
 
 #include "pch.h"
 #include "RadixToStringConverter.h"
-#include "CalcManager/Header Files/CalcEngine.h"
+#include "CalcManager/Header Files/RadixType.h"
 #include "CalcViewModel/Common/AppResourceProvider.h"
 
 using namespace Platform;