Rename transfer action request models for .NET to satisfy AZC0030 (#45719)

The three transfer action body models trip the .NET analyzer AZC0030, which rejects model names ending in 'Request'. This failed the azure-sdk-for-net PR validation build for Azure.ResourceManager.Quota.

Adds csharp-scoped @clientName aliases so only the .NET surface changes. openapi.json is byte-identical, so the wire contract, the other four language SDKs, and the 2025-09-01 stable version are all unaffected.

Also removes the pre-existing csharp-model-suffix suppressions. Their justification ('Name kept for backward compatibility') was invalid since all three models are @added in 2026-09-01-preview, and the suppression had no effect on AZC0030, which runs downstream in the .NET repo.