Add dynamic keys on useMotion directives when calling apply() and other methods

[alex-eliot]

@Tahul Adding support for strict typing of the directive keys when creating a motion instance using useMotion and other methods.

I've also added a few other // @ts-expect-error that seemed to be missing and caused tsc to throw errors. I believe it is cleaner to do it this way rather than do keyof typeof obj in every place, since it's something that TypeScript don't intend to change (https://github.com/microsoft/TypeScript/pull/12253#issuecomment-263132208).

[Tahul]

Nice work :)

I think we can get rid of these @ts-expect-error in another PR.