feat: [ConfidentialComputing] add Nvidia Attestation proto message with its relevant fields and ConfidentialGke options (#8906)

* feat: add Nvidia Attestation proto message with its relevant fields and ConfidentialGke options

PiperOrigin-RevId: 866189208

Source-Link: googleapis/googleapis@4e434c1

Source-Link: googleapis/googleapis-gen@7c27350
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ConfidentialComputing/metadata/V1/Service.php

@@ -31,6 +31,13 @@
 
 /**
  * Lists information about the supported locations for this service.
+This method can be called in two ways:
+
+*   **List all public locations:** Use the path `GET /v1/locations`.
+*   **List project-visible locations:** Use the path
+`GET /v1/projects/{project_id}/locations`. This may include public
+locations as well as private or other locations specifically visible
+to the project.
  *
  * This sample has been automatically generated and should be regarded as a code
  * template only. It will require modifications to work:

ConfidentialComputing/samples/V1/ConfidentialComputingClient/list_locations.php

@@ -403,6 +403,13 @@ public function getLocation(GetLocationRequest $request, array $callOptions = []
 
     /**
      * Lists information about the supported locations for this service.
+    This method can be called in two ways:
+
+    *   **List all public locations:** Use the path `GET /v1/locations`.
+    *   **List project-visible locations:** Use the path
+    `GET /v1/projects/{project_id}/locations`. This may include public
+    locations as well as private or other locations specifically visible
+    to the project.
      *
      * The async variant is {@see ConfidentialComputingClient::listLocationsAsync()} .
      *