GeoDR creation succeed even when server do not exist

**Describe the bug**
When setting up Azure SQL GeoDR, the AZ CLI executes correctly even if the server specified in --server do not exist

**To Reproduce**
az sql db replica create --name --server --resource-group --partner-server

Make sure that do not exists, while database and exists.

**Expected behavior**
En error, saying that do not exists

**Environment summary**
```
Linux-4.4.0-18362-Microsoft-x86_64-with-debian-buster-sid
Python 3.6.5
Shell: bash

azure-cli 2.0.74
```