fix: Correct logic error in tool input assignment for ChatflowTool (#3903)

The previous code incorrectly assigned `toolInput` to an empty string when `customInput` was non-empty. Corrected the logic to ensure that `toolInput` is assigned `customInput` when `useQuestionFromChat` is false and `customInput` is non-empty.

packages/components/nodes/tools/ChatflowTool/ChatflowTool.ts

@@ -164,7 +164,7 @@ class ChatflowTool_Tools implements INode {
         let toolInput = ''
         if (useQuestionFromChat) {
             toolInput = input
-        } else if (!customInput) {
+        } else if (customInput) {
             toolInput = customInput
         }