Fix flowlog crash

[nnbu]

Issue #, if available: #1931

Description of changes:
While creating FlowLog, if logDestnation does not exist then CreateFlowLogsWithContext does not return the error. However, Unsuccessful field in the response is set. FlowLog is not created in aws. Due to this, controller crashes while accessing the flow log id from the response (resp.FlowLogIds[0]).
Fixing the issue by checking if FlowLogIds has valid length before accessing it.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ack-prow]

Hi @nnbu. Thanks for your PR.

I'm waiting for a aws-controllers-k8s member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[a-hilaly]

/ok-to-test

[ack-bot]

Issues go stale after 180d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 60d of inactivity and eventually close.
If this issue is safe to close now please do so with /close.
Provide feedback via https://github.com/aws-controllers-k8s/community.
/lifecycle stale

[ack-bot]

Stale issues rot after 60d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 60d of inactivity.
If this issue is safe to close now please do so with /close.
Provide feedback via https://github.com/aws-controllers-k8s/community.
/lifecycle rotten

[nnbu]

/test ec2-kind-e2e

[a-hilaly]

/lgtm

[ack-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: a-hilaly, nnbu

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[a-hilaly]

/retest

[ack-prow]

@nnbu: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ec2-verify-attribution	776af5a	link	false	/test ec2-verify-attribution

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.