Add support for FloatValueProvider to CoreAnimation rendering engine

[opfeffer]

Opening issue as per discussion: https://github.com/airbnb/lottie-ios/discussions/1836#discussioncomment-4334493

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Which Version of Lottie are you using?

Lottie 4.0.0

Expected Behavior

Setting custom opacity using the FloatValueProviders is supported by CoreAnimation rendering engine.

Actual Behavior

Lottie asserts when any value provider provided other than color (see ValueProviderStore.swift).

Animation JSON

<Don't have a super trivial handy at this time but can potentially make time to create one if needed>