[APIM] The service could not be restored immediately after soft deletion

The APIM service `acctestAM-test` could not be restored immediately after soft deletion succeeds. The details are as follows. It is worth mentioning that if you wait for a while (about 1 minute) after step2, the restore could succeed. We look forward to recovering immediately after a successful soft delete. If it is by design, I assume that a status should be returned to let us know when the deleted service could be restored, right? For example: append the status field in the response of [DeletedServices_GetByName](https://github.com/Azure/azure-rest-api-specs/blob/d3edca94ae4ddb854e88142cba6a7337ef1a5eed/specification/apimanagement/resource-manager/Microsoft.ApiManagement/stable/2022-08-01/apimdeletedservices.json#L81C13-L81C13) API.

step1. Confirm `acctestAM-test` does not exist after soft deletion:
```
AzureRM Request:
GET /subscriptions/.../resourceGroups/acctestRG-test/providers/Microsoft.ApiManagement/service/acctestAM-test?api-version=2022-08-01 HTTP/1.1
Host: management.azure.com
User-Agent: HashiCorp/go-azure-sdk (Go-http-Client/1.1 apimanagementservice/2022-08-01) HashiCorp Terraform/1.5.1 (+https://www.terraform.io) Terraform Plugin SDK/2.10.1 terraform-provider-azurerm/dev pid-222c6c49-1b0a-5959-a213-6608f9eb8820
Content-Type: application/json; charset=utf-8
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
Accept-Encoding: gzip

AzureRM Response for https://management.azure.com/subscriptions/.../resourceGroups/acctestRG-test/providers/Microsoft.ApiManagement/service/acctestAM-test?api-version=2022-08-01:
HTTP/2.0 404 Not Found
Content-Length: 138
Cache-Control: no-cache
Content-Type: application/json; charset=utf-8
Date: Thu, 10 Aug 2023 05:21:46 GMT
Expires: -1
Pragma: no-cache
Server: Microsoft-HTTPAPI/2.0
Strict-Transport-Security: max-age=31536000; includeSubDomains
X-Content-Type-Options: nosniff
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
X-Ms-Ratelimit-Remaining-Subscription-Reads: 11998
X-Ms-Request-Id: 85972085-5b34-4d1a-8709-b075fb8deb45
X-Ms-Routing-Request-Id: SOUTHEASTASIA:20230810T052146Z:85972085-5b34-4d1a-8709-b075fb8deb45

{"error":{"code":"ServiceNotFound","message":"Api service does not exist: acctestAM-test","details":null,"innerError":null}}

```
step2. Get `acctestAM-test` exist in deletedServices:
AzureRM Request:
```
GET /subscriptions/.../providers/Microsoft.ApiManagement/locations/eastus/deletedServices/acctestAM-test?api-version=2022-08-01 HTTP/1.1
Host: management.azure.com
User-Agent: HashiCorp/go-azure-sdk (Go-http-Client/1.1 deletedservice/2022-08-01) HashiCorp Terraform/1.5.1 (+https://www.terraform.io) Terraform Plugin SDK/2.10.1 terraform-provider-azurerm/dev pid-222c6c49-1b0a-5959-a213-6608f9eb8820
Content-Type: application/json; charset=utf-8
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
Accept-Encoding: gzip

AzureRM Response for https://management.azure.com/subscriptions/.../providers/Microsoft.ApiManagement/locations/eastus/deletedServices/acctestAM-test?api-version=2022-08-01:
HTTP/2.0 200 OK
Cache-Control: no-cache
Content-Type: application/json; charset=utf-8
Date: Thu, 10 Aug 2023 05:21:47 GMT
Expires: -1
Pragma: no-cache
Server: Microsoft-HTTPAPI/2.0
Strict-Transport-Security: max-age=31536000; includeSubDomains
Vary: Accept-Encoding
X-Content-Type-Options: nosniff
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
X-Ms-Ratelimit-Remaining-Subscription-Reads: 11999
X-Ms-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
X-Ms-Routing-Request-Id: SOUTHEASTASIA:20230810T052148Z:c7fa4ff2-6126-4764-8704-332f2a06b056

{"id":"/subscriptions/.../providers/Microsoft.ApiManagement/locations/eastus/deletedservices/acctestAM-test","name":"acctestAM-test","type":"Microsoft.ApiManagement/deletedservices",
"location":"East US","properties":{"serviceId":"/subscriptions/.../resourceGroups/acctestRG-test/providers/Microsoft.ApiManagement/service/acctestAM-test",
"scheduledPurgeDate":"9999-12-31T23:59:59.9999999","deletionDate":"2023-08-10T05:20:59.810718Z"}}

```

step3. Restore the `acctestAM-test` =>error occurred.
```
AzureRM Request:
PUT /subscriptions/.../resourceGroups/acctestRG-test/providers/Microsoft.ApiManagement/service/acctestAM-test?api-version=2022-08-01 HTTP/1.1
Host: management.azure.com
User-Agent: HashiCorp/go-azure-sdk (Go-http-Client/1.1 apimanagementservice/2022-08-01) HashiCorp Terraform/1.5.1 (+https://www.terraform.io) Terraform Plugin SDK/2.10.1 terraform-provider-azurerm/dev pid-222c6c49-1b0a-5959-a213-6608f9eb8820
Content-Length: 132
Content-Type: application/json; charset=utf-8
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
Accept-Encoding: gzip

{"location":"eastus","properties":{"restore":true},"sku":{"capacity":0,"name":"Consumption"}}

AzureRM Response for https://management.azure.com/subscriptions/.../resourceGroups/acctestRG-test/providers/Microsoft.ApiManagement/service/acctestAM-test?api-version=2022-08-01:
HTTP/2.0 400 Bad Request
Content-Length: 141
Cache-Control: no-cache
Content-Type: application/json; charset=utf-8
Date: Thu, 10 Aug 2023 05:21:49 GMT
Expires: -1
Pragma: no-cache
Server: Microsoft-HTTPAPI/2.0
Strict-Transport-Security: max-age=31536000; includeSubDomains
X-Content-Type-Options: nosniff
X-Ms-Correlation-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
X-Ms-Ratelimit-Remaining-Subscription-Resource-Requests: 23999
X-Ms-Request-Id: d2cee4f3-883e-ce55-1910-78d3d39ce805
X-Ms-Routing-Request-Id: SOUTHEASTASIA:20230810T052150Z:9cc60d65-86ca-4d9e-bd60-fb55a626128c

{"error":{"code":"InvalidOperation","message":"Unable to undelete service 'acctestAM-test'.","details":null,"innerError":null}}

```

Start with specification/apimanagement/resource-manager/Microsoft.ApiManagement/stable/2022-08-01/apimdeletedservices.json and the DeletedServices_GetByName operation. Compare its response with the restore request and the reported InvalidOperation response. Done means the API behavior or contract clearly indicates when a soft-deleted service can be restored, with the required specification change identified.

Written by the indexing model from the issue text.