Add Microsoft.HybridConnectivity stable API version 2027-01-01 (GCP connector GA) (#45480)

* Add Microsoft.HybridConnectivity stable API version 2027-01-01 (GCP connector GA)

GA the GCP public cloud connector surface, ported from the validated
preview work in azure-rest-api-specs-pr (2025-12-01-preview through
2026-09-01-preview) and re-gated to the new stable version.

Includes:
- GCP cloud profile, project and organization properties
- HostType.GCP and connector kind
- GenerateGcpTemplate operation with GcpTemplateFormat
  (terraform / shellscript) and template response
- hostTypes on the solution type models
- awsCloudProfile made optional beginning in 2027-01-01
- 48 examples for 2027-01-01 and the generated stable swagger

Excluded from GA: the subscriptionPool property and the GVMO service
names, neither of which is part of this GA scope.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 5efd3f64-66de-44b1-b642-8ca41a4ef744

* Add C# client name for GenerateGcpTemplateRequest

The csharp-model-suffix rule requires models ending in 'Request' to use
a 'Content' suffix for C#. Mirrors the existing GenerateAwsTemplateRequest
customization, keeping the wire contract name unchanged.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 5efd3f64-66de-44b1-b642-8ca41a4ef744

* Add justification for arm-resource-invalid-envelope-property suppression

The suppression on the 'kind' property carried an empty justification
string, which blocks the TypeSpec Suppressions review check.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 5efd3f64-66de-44b1-b642-8ca41a4ef744

* Remove stale no-empty-model suppression on GenerateGcpTemplateResponse

The model declares a 'template' property, so the no-empty-model rule
does not apply. The suppression was inherited from an earlier revision
where the model had no properties, and it carried no justification.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 5efd3f64-66de-44b1-b642-8ca41a4ef744

* Exclude 2026-04 preview changes from GCP GA

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

Copilot-Session: a9dfda9f-681a-42d1-ac1c-a8f239f03843

* Justify empty GCP template response

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

Copilot-Session: a9dfda9f-681a-42d1-ac1c-a8f239f03843

* Remove redundant GCP organization flag

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

Copilot-Session: a9dfda9f-681a-42d1-ac1c-a8f239f03843

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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 5efd3f64-66de-44b1-b642-8ca41a4ef744
Copilot-Session: a9dfda9f-681a-42d1-ac1c-a8f239f03843