Merge `@sharedRoute` operations into one

https://azure.github.io/typespec-azure/docs/howtos/generate-client-libraries/04method/#merge-sharedroute-operations-into-one

If your shared routes are actually one unique semantic operation, you may want to configure codegen to use a unique name. This is simply done by renaming both operations to the same name using `@clientName`

typespec:
```
@sharedRoute
@route("/foo")
op a(x: int) : float

@sharedRoute
@route("/foo")
op b(x: string) : int64

// client.tsp
import "./main.tsp";
import "@azure-tools/typespec-client-generator-core";

using Azure.ClientGenerator.Core;

@@clientName(a, "Foo");
@@clientName(b, "Foo");
```