User/regisb/fix mux release pipeline fragility5 (#4530)

* Fixing NavigationView verification files

* Workaround for robocopy fragility

Author: RBrid

tools/InternalWindowsSDKNuget/MergeNupkgParts.cmd

@@ -13,6 +13,7 @@ REM - 0x0 for no files copied,
 REM - 0x1 for files copied, (https://support.microsoft.com/en-us/kb/954404)
 REM - 0×2 for Some Extra files or directories were detected. Some housekeeping may be needed.
 IF %ERRORLEVEL%==1 set ERRORLEVEL=0
+IF %ERRORLEVEL%==2 set ERRORLEVEL=0
 IF %ERRORLEVEL%==3 set ERRORLEVEL=0
 
 exit /B %ERRORLEVEL%