feature(unlock-app): Update ToastHelper imports

[0xTxbi]

Description

This PR introduces changes that updates unlock-app to use ToastHelper from the ui package.

Issues

Fixes #
Refs #

Checklist:

• 1 PR, 1 purpose: my Pull Request applies to a single purpose
• I have commented my code, particularly in hard-to-understand areas
• I have updated the docs to reflect my changes if applicable
• I have added tests (and stories for frontend components) that prove my fix is effective or that my feature works
• I have performed a self-review of my own code
• If my code involves visual changes, I am adding applicable screenshots to this thread

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
unlock-airdrops	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Feb 26, 2025 11:59pm

2 Skipped Deployments

Name	Status	Preview	Comments	Updated (UTC)
unlock-static-site	⬜️ Ignored (Inspect)			Feb 26, 2025 11:59pm
unlock-storybook	⬜️ Ignored (Inspect)			Feb 26, 2025 11:59pm

[julien51]

Lots of toasts!