SnackBar

### Description

https://api.flutter.dev/flutter/material/SnackBar-class.html?_gl=1*1tcb8t6*_ga*MTc4NDk1MjEwMS4xNzMyNzc5Njk1*_ga_04YGWK0175*MTc0MjQwODM3MS4xMDEuMS4xNzQyNDA5MTUzLjAuMC4w

#### This issue affects other repositories. To successfully solve the problem, you also need to add updates to the appropriate packages

Affected packages:
- [duit_js](https://github.com/Duit-Foundation/duit_js)
- [duit_go](https://github.com/Duit-Foundation/duit_go)

Start with the linked Flutter SnackBar API documentation, then inspect how flutter_duit represents and renders comparable UI components. Check the affected duit_js and duit_go packages as well. Done means the intended SnackBar support is defined and implemented consistently across all three repositories, with their relevant validation updated.

Written by the indexing model from the issue text.