LibJS: Use implicit ThrowCompletionOr<T> constructor where possible

Luckily this is not very widespread yet as most of it would happen in
the various JS functions instead of AOs.

Userland/Libraries/LibJS/Runtime/ProxyObject.cpp

@@ -312,7 +312,7 @@ ThrowCompletionOr<Optional<PropertyDescriptor>> ProxyObject::internal_get_own_pr
     }
 
     // 18. Return resultDesc.
-    return { result_desc };
+    return result_desc;
 }
 
 // 10.5.6 [[DefineOwnProperty]] ( P, Desc ), https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc