Fix dynamic plugin discovery for x64-under-arm64 macOS

Signed-off-by: falkTX <falktx@falktx.com>

source/discovery/carla-discovery.cpp

@@ -2774,8 +2774,6 @@ int main(int argc, const char* argv[])
     if (openLib && handle != nullptr)
         lib_close(handle);
 
-    gPipe = nullptr;
-
     if (retryAsX64lugin)
     {
        #if defined(CARLA_OS_MAC) && defined(__aarch64__)
@@ -2798,6 +2796,8 @@ int main(int argc, const char* argv[])
        #endif
     }
 
+    gPipe = nullptr;
+
     // ----------------------------------------------------------------------------------------------------------------
 
   #ifdef CARLA_OS_WIN