[http-client-csharp] remove property `ResourceName` in `InputOperation`

[ArcturusZhang]

This ResourceName property was something that we copied from autorest.csharp repo, but now it makes no sense.
Previously we use this to determine the name of a client - now obviously we are using something else.
When I check the usage of this property, it is never used.
We should remove it.

[jorgerangel-msft]

Dapeng Zhang (@ArcturusZhang) is this still in progress?

[JoshLove-msft]

We can remove the unused property