ServiceBus api-version update (#45817)

* Bump ServiceBus C# mgmt emitter api-version to 2026-07-01-preview

The @azure-typespec/http-client-csharp-mgmt emitter was pinned to 2026-01-01, so Azure.ResourceManager.ServiceBus could not be regenerated at 2026-07-01-preview reproducibly. Only the C# mgmt emitter is changed; the provisioning emitter stays on 2026-01-01.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 1271ded5-2e2a-4889-98b5-0e2c0f608823

* updates

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Copilot-Session: 1271ded5-2e2a-4889-98b5-0e2c0f608823