Import: Simplify handling of Resource_FormatType

The type Resource_FormatType already exists since 2015. So, its usage doesn't require pre-processor macros everywhere.

src/Mod/Import/App/AppImportPy.cpp

@@ -157,16 +157,9 @@ private:
             hApp->NewDocument(TCollection_ExtendedString("MDTV-CAF"), hDoc);
 
             if (file.hasExtension({"stp", "step"})) {
-#if OCC_VERSION_HEX >= 0x070800
-                Resource_FormatType cp = Resource_FormatType_UTF8;
-#endif
                 try {
                     Import::ReaderStep reader(file);
-#if OCC_VERSION_HEX < 0x070800
                     reader.read(hDoc);
-#else
-                    reader.read(hDoc, cp);
-#endif
                 }
                 catch (OSD_Exception& e) {
                     Base::Console().Error("%s\n", e.GetMessageString());