"The maximum number of VPCs has been reached" test failure causing flakes

[nrb]

/kind flake
/triage accepted

What steps did you take and what happened:
[A clear and concise description of what the bug is.]

CI jobs are often failing with

failed to create new managed VPC: failed to create vpc: The maximum number of VPCs has been reached

This happens on unit tests, and sometimes the unit tests still pass despite this reported failure. See here for one such case.

What did you expect to happen:

CI would not fail on VPC limits so often.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

This code is found in

cluster-api-provider-aws/controllers/awscluster_controller_test.go

Line 569 in dcea94f

g.Expect(err.Error()).To(ContainSubstring("The maximum number of VPCs has been reached"))

. Initially, some maintainers thought this was a boskos provisioning problem, but it's something within our own test suit.

Environment:

• Cluster-api-provider-aws version: main, over several months
• Kubernetes version: (use kubectl version): 1.28 and later