Add new arg type for set and delete to support what-if #1361
Description
Summary of the new feature / enhancement
Need a way to specify to delete to run in what-if mode. Currently we have a dedicated operation in the resource manifest for whatif, but it only applies to set. We should deprecate that operation and instead have a new argKind whatIfArg that gets passed if set or delete is being run in what-if mode and the engine can see if this arg is in the arg list to determine if it falls back to synthetic what-if
Proposed technical implementation details (optional)
No response