Enhance typing for intrinsic type

[tadelesh]

Current logic, all intrinsic type will convert to unknown which is not correct, need to be fixed.

typespec-azure/packages/typespec-client-generator-core/src/types.ts

Lines 206 to 214 in 95dcda6

	if (context.program.checker.isStdType(type) || type.kind === "Intrinsic") {
	let kind: SdkBuiltInKinds = "any";
	if (type.kind === "Scalar") {
	kind = getScalarKind(type);
	}
	return {
	...getSdkTypeBaseHelper(type, kind),
	encode: getEncodeHelper(context, type, kind),
	};

[tadelesh]

Intrinsic types contain: ErrorType, void, never, unknown, null.
ErrorType: I have no idea when we will get this type. Currently, it seems nowhere for operation, parameter, properties and so on. @timotheeguerin could you give some hint?
void, never: I think we will not get such types if we use the API provided by compiler.
unknown: to any.
null: I think it is only used in union as string | null and it is handled in union types as nullable, we don't need to take care of it separately unless there is any scenario that I'm not aware of.

[tadelesh]

Close for now since there is no real case which has such problem.