LibJS: Enable EXPLICIT_SYMBOL_EXPORT

Author: https://github.com/ayeteadoe
Commit: c14173f651
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5215
Reviewed-by: https://github.com/ADKaster ✅

Libraries/LibJS/Runtime/WeakRef.h

@@ -12,7 +12,7 @@
 
 namespace JS {
 
-class WeakRef final
+class JS_API WeakRef final
     : public Object
     , public GC::WeakContainer {
     JS_OBJECT(WeakRef, Object);