Bug: Handle InvalidApiVersionParameter on Empty ResourceGroup / Gracefully handle 400 errs

[melonrush13]

We should remove 'omitempty' from the types files for Resourcegroup from AzureSqlServer types. file and also other types if the issue exists. This will ensure that we catch the error if resourcegroup is not specified which causes this issue.

Describe the bug

The following error occurs for creating a V1Alpha1 azuresqlserver with an empty resource group or invalid named resourcegroup.

"Error": "sql.ServersClient#Get: Failure responding to request: StatusCode=400 -- Original Error: autorest/azure: Service returned an error. Status=400 Code=\"InvalidApiVersionParameter\" Message=\"The api-version '2015-05-01-preview' is invalid. The supported versions are '2020-01-01,2019-11-01,2019-10-01,2019-09-01,2019-08-01,2019-07-01,2019-06-01,2019-05-10,2019-05-01,2019-03-01,2018-11-01,2018-09-01,2018-08-01,2018-07-01,2018-06-01,2018-05-01,2018-02-01,2018-01-01,2017-12-01,2017-08-01,2017-06-01,2017-05-10,2017-05-01,2017-03-01,2016-09-01,2016-07-01,2016-06-01,2016-02-01,2015-11-01,2015-01-01,2014-04-01-preview,2014-04-01,2014-01-01,2013-03-01,2014-02-26,2014-04'.\"", "Instance": "default/sqlserver-sample-777"}

To Reproduce
Steps to reproduce the behavior:
k create -f config/samples/azure_v1alpha1_azuresqlserver.yaml
My Resource Group Name: resourcegroup-azure-operators-mel

Expected behavior
Gracefully handle 400 errors (similarly to how Redis Cache handles future errs)

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.

[jananivMS]

We should remove 'omitempty' from the types files for Resourcegroup from AzureSqlServer types. file and also other types if the issue exists. This will ensure that we catch the error if resourcegroup is not specified which causes this issue.

[matthchr]

@melonrush13 were you testing this in kind, or in an AKS cluster with webhooks enabled?

This error definitely happens when resourceGroup is empty, but that's not actually possible based on the CRD (it's required for both v1alpha1 and v1beta). It's possible to get an resourceGroup string if you create a v1alpha1 resource with webhooks disabled though (because conversion from v1alpha1 -> v1beta1 wasn't run).

I've filed an issue for the Go SDK folks since the SDK is supposed to do this check, but in the meantime I've updated the controller to check this manually and give a better error in #1232132