Apply NestedInput initial values

This update applies the initial values for nested inputs (as set in the Inputs panel of the Editor), so that NestedInputs behave in the same way as regular StateMachineInputs. There are a couple of reasons to do this:

1. Currently if you have a nested artboard and set the initial nested input value, it will only apply in the editor when viewing that artboard. If you nest that artboard in another artboard, the initial values do not apply. Similarly, initial nested values do not apply in the runtimes. Currently StateMachineInputs do apply initial values, so this brings NestedInputs in line with that.

2. There was a bug Hernan noticed where there in certain cases, NestedInput values that were keyed on a timeline did not apply properly in cases where the keyed value was the same as the default value. In these cases, the keyed value is ignored because it and the default values were the same. In addition, since the initial value wasn't being applied, the state wasn't being update properly based on the nested input's value.

Diffs=
6d9aa0179 Apply NestedInput initial values (#6140)

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