endpoint resource: fix terminal condition showing up in recoverable

[surajkota]

Description of Changes

• aws-controllers-k8s/sagemaker-controller#7 introduced ability to set terminal conditions for failed update scenarios by returning an error (FailUpdateError) from customUpdateEndpoint method and catching it in customUpdateConditions

• aws-controllers-k8s/code-generator#40 added a catch block for all errors which are non-terminal which executes before customUpdateConditions. Since FailUpdateError is a custom error, it started showing up in recoverable in addition to terminal condition once recoverable condition was introduced. Example:

"conditions": [
           ...
            {
                "message": "Unable to update Endpoint. Check FailureReason",
                "status": "True",
                "type": "ACK.Recoverable"
            },
            {
                "message": "Unable to update Endpoint. Check FailureReason",
                "status": "True",
                "type": "ACK.Terminal"
            }
        ],

This PR fixes this issue by creating making FailUpdateError an awserr type of error and using it as one of the terminal codes just like any other AWS error. This also simplifies the custom code in customUpdateConditions which now only needs to check for Status.EndpointStatus == Failed while setting terminal condition

---

• Removes a redundant check for if ko.Status.Conditions == nil because all methods - sdkCreate, sdkFind, sdkUdpate and updateConditions - set it to an empty list already

Testing

Locally using pytest and manually

(ack) ubuntu@ip-172-31-0-119:~/go/src/github.com/aws-controllers-k8s/sagemaker-controller/test/e2e$ PYTHONPATH=. pytest -n 4 --dist loadfile
=============================================== test session starts ===============================================
platform linux -- Python 3.8.8, pytest-6.2.3, py-1.10.0, pluggy-0.13.1
rootdir: /home/ubuntu/go/src/github.com/aws-controllers-k8s/sagemaker-controller/test/e2e
plugins: xdist-2.2.0, forked-1.3.0, black-0.3.12
gw0 [24] / gw1 [24] / gw2 [24] / gw3 [24]
........................                                                                                    [100%]
========================================= 24 passed in 1866.80s (0:31:06) =========================================

[jkuruba]

Neat