Adds succesfull lts/proxies migration & testsuite

qt6-after/qt6-migrated-legatus/Lts/Proxies/Buildings/BuildingControlUnit/Json/CMakeLists.txt

@@ -4,9 +4,9 @@
 # $Author$
 #
 
-# Make ${Qt6_WebSockets} optional
-if(QT6_GUI_AVAILABLE AND TARGET Qt6::WebSockets)
-  set(Qt6_WebSockets ${Qt6_WebSockets})
+# Make ${Qt6_WebSockets} optional (doesn't require GUI)
+if(TARGET Qt6::WebSockets)
+  set(Qt6_WebSockets Qt6::WebSockets)
 else()
   set(Qt6_WebSockets "")
 endif()