Expose `mongoEndpoint` property in the Cosmos DB API

When creating Cosmos DB Account of kind MongoDB using terraform, the endpoint `https://demo-cosmos-mangodb.documents.azure.com:443` is returned instead of the expected `mongoEndpoint` `https://demo-cosmos-mangodb.mongo.cosmos.azure.com:443/`.

The property `mongoEndpoint` is not currently exposed in the [current version of the API](https://github.com/Azure/azure-rest-api-specs/blob/41645a4769694a7d63a2514b45146ec369eeb273/specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2022-08-15/cosmos-db.json#L6073).

This needs to be exposed in order for Terraform to provide the correct value as an output.
This was initial raised in the terraform Azurerm provider project, but needs to be added to the API first.
https://github.com/hashicorp/terraform-provider-azurerm/issues/20306

Open the linked specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2022-08-15/cosmos-db.json at the cited section and inspect the Cosmos DB account properties. Compare the MongoDB account response with the requested mongoEndpoint property; done means the API exposes that property so Terraform can return the expected endpoint.

Written by the indexing model from the issue text.