TSL: Fix optional parameter in `Fn()` (#30293)

src/nodes/tsl/TSLCore.js

@@ -305,7 +305,7 @@ class ShaderCallNodeInternal extends Node {
 		} else {
 
 			const jsFunc = shaderNode.jsFunc;
-			const outputNode = inputNodes !== null ? jsFunc( inputNodes, builder ) : jsFunc( builder );
+			const outputNode = inputNodes !== null || jsFunc.length > 1 ? jsFunc( inputNodes || [], builder ) : jsFunc( builder );
 
 			result = nodeObject( outputNode );