fix: corrections to handleHttp and handleUnverified

Changed handleHttpCallbackUnverified to be async and stripped query parameters when validating signature of handleHttpCallback requests.

Types of changes

[x] 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 change)
[x] I have read the CONTRIBUTING document
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[ ] Any required documentation has been added
[ ] I have added tests to cover my changes