🐛 Fix cluster deletion when using BYO AWS infra mode and Secondary CIDR

[adriananeci]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Currently, cluster deletion is failing when using BYO AWS infra mode (https://cluster-api-aws.sigs.k8s.io/topics/bring-your-own-aws-infrastructure.html#tagging-aws-resources) with:

Events:
  Type     Reason                           Age                       From            Message
  ----     ------                           ----                      ----            -------
  Warning  FailedDisassociateSecondaryCidr  2m27s (x3471 over 3h21m)  aws-controller  (combined from similar events): Failed disassociating secondary CIDR "100.64.0.0/16" from VPC InvalidCidrBlock.InUse: The vpc vpc-021b2fd5f5a7df0bc currently has a subnet within CIDR block 100.64.0.0/16
           status code: 400, request id: fdddb61f-a01f-49ed-90a7-0489532ad351

While using the BYO AWS infra mode, VPC secondary CIDRs shouldn't be disassociated during cluster deletion.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Checklist:

• squashed commits
• includes documentation
• includes emojis
• adds unit tests
• adds or updates e2e tests

Release note:

Fix cluster deletion when using BYO AWS infra mode and Secondary CIDR

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign vincepri for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[JonnieDoe]

/lgtm

[k8s-ci-robot]

@JonnieDoe: changing LGTM is restricted to collaborators

In response to this:

/lgtm

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-sigs/prow repository.

[AndiDog]

/lgtm