WIP: fix parsing dynamic pseudo type

[t0yv0]

Toward fixing #3078

Surprisingly this still cannot pass the test because it is now doing:

priorState.Value.Diff(plannedStateValue)

and that somehow blows up in the presence of values with DynamicPseudoType type.

I get this:

        stderr: error: AttributeName("dyn"): Error converting tftypes.Number<"42"> (value2) at "AttributeName(\"dyn\")": can't unmarshal tftypes.Number into *string, expected string

[t0yv0]

Reminder to self: tuples don't yet fully integrate through RawStateDelta so tuple paths are not there.

[VenelinMartinov]

superseded by #3099