test: adds unit tests for useToastsInternal hook

[Nandinibajaj16]

Description

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Closes #130

What change does this PR introduce?

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• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update (changes to docs/code comments)

What is the proposed approach?

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Checklist:

• [ ] The commit message follows our adopted guidelines
• [ ] Testing has been done for the change(s) added (for bug fixes/features)
• [ ] Relevant comments/docs have been added/updated (for bug fixes/features)