fix(useTransition): fix regression with non-linear transition functions

[scottbedard]

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Description

There was a regression with useTransition during the change from unref → toValue. Non-linear custom easing functions were returning NaN. This is due to toValue first doing it's own function check, and returning the output of that function rather than the function itself.

This didn't break linear transitions because those are essentially just identity-functions, which return undefined when no input is provided. This led to using the right side of toValue(...) ?? linear, and therefor the default linear transition. With non-linear transitions however, that numeric input is necessary, and without it we end up doing arithmetic on undefined, which leads to the NaN.

I've fixed this with a manual function check, and included a test to cover this situation. Alternatively, we could use the default unref function here to avoid the redundant type checking.

Additional context

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🤖 Generated by Copilot at fe1ec45

This pull request adds support for custom easing functions to the useTransition function. It modifies the executeTransition function to handle function parameters and adds a test case to verify the functionality.

🤖 Generated by Copilot at fe1ec45

• Allow custom easing functions for useTransition (link, link)

• Add a test case to verify non-linear easing with easeInQuad function (link)