[typespec-ts] Add support for skipping the final resource fetch in LRO

Codegen support as it relates to https://github.com/Azure/azure-sdk-for-js/issues/32142

I am okay with this in KeyVault since we will not expose this operation option e.g `PreFullRestoreOperationOptionalParams` to public but I think there are still some dicussions on how to adopt this feature in codegen side.

Two facts here:
- The `skipFinalGet` is an operation-level configuration and it should be fixed and should be an implementation detail for that operation, so exposing to public doesn't make any sense.
- When we try to enable this `skipFinalGet` this usually means we need customizations because the generated return type or ser/deser logic may not what we want. So generally this option should not appear in standard LROs.

So simply adding this option in codegen may not what we want. Could you create an issue in codegen side? I could help follow up this.

_Originally posted by @MaryGao in https://github.com/Azure/azure-sdk-for-js/pull/33286#discussion_r2007002329_