use types.Unalias() throughout in preparation for gotypesalias=1 related to https://github.com/golang/open2opaque/issues/11 PiperOrigin-RevId: 720589086 Change-Id: I7ec7f12886e9a3fb99c02f7247c7437ec17c3581
The open2opaque tool migrates Go packages from the Go Protobuf Open Struct API to the Opaque API.
For documentation, see: