fix: fix typo, `ForgettenSubtree` -> `ForgottenSubtree`

[bajpai244]

closes: #636

This PR:

• Fixes typo for the identifier bu changing it from ForgettenSubtree to ForgottenSubtree

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• [x] Targeted PR against correct branch (main)
• [x] Linked to GitHub issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• [ ] Wrote unit tests
• [ ] Updated relevant documentation in the code
• [x] Added relevant changelog entries to the CHANGELOG.md of touched crates.
• [x] Re-reviewed Files changed in the GitHub PR explorer

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