[fix] load function should not leak props

[rmunn]

Fixes #2133.

When navigating from a page with a load() function to a page without a load() function, props were not being reset, so if the second page had a prop with the same name as the prop returned by the first page's load() function, the second page would receive the same prop that the first page did.

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[benmccann]

thank you!!