Add ValueListenableBuilder Widget to the Widget Catalog

ValueListenablBuilder Widget needs to be added to the Widget Catalog. Read `How to contribute to the Widget Catalog` in the [README](https://github.com/ACM-VIT/fludget/blob/master/README.md) for detailed steps. Make sure to include all the arguments(name, implementation, description, codeString, link and category). Refer to any widget in `widgetList.dart` and its own `*widget*.dart` file for better understanding. Showcase all properties of the widget. (Refer to the official docs in case of any doubts)
Please attach screen recording of the same once done in the PR.

Start with the “How to contribute to the Widget Catalog” section in README, then inspect widgetList.dart and an existing widget’s *widget*.dart file. Add ValueListenableBuilder with all requested catalog arguments and showcase its properties; the PR should also include a screen recording.

Written by the indexing model from the issue text.