Add EvalContext argument for Expression.GetType and ParamMarker.GetUserVar

[YangKeao]

Enhancement

Ref #53485 (comment). As the actual type and internal datum depend on the context, we should explicitly pass the context through the argument, rather than store it in the ParamMarker. It'll be a big change.

It'll introduce three modification:

1. Remove the ctx in ParamMarker.
2. Add EvalContext argument for Expression.GetType.
3. Add EvalContext argument for String (replace String with StringWithCtx)

The most concerning issue is that the .String() method cannot accept a parameter. We should analyze the usage of it carefully. Sometimes, returning a simple ? is enough, but it's not always good to do so. If not, we can Eval it, or provide another function to get the debug output with context 🤔 .