Guard network detector tests by feature

Compile the Windows detector tests only when HAVE_MAT_NETDETECT is enabled so compact custom SKUs that omit the detector still build the test project.

Verified at:
- tests/unittests/NetworkDetectorTests.cpp
- Solutions/build.compact.props

Files changed:
- tests/unittests/NetworkDetectorTests.cpp

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: df9f344e-e064-404e-ae6f-c0ef455d747c

Author: bmehta001

tests/unittests/NetworkDetectorTests.cpp

@@ -2,7 +2,7 @@
 
 #include "common/Common.hpp"
 
-#ifdef _WIN32
+#if defined(_WIN32) && defined(HAVE_MAT_NETDETECT)
 #include "pal/desktop/NetworkDetector.hpp"
 
 using namespace MAT;