Specified test namespace not created when running TestSuite

[Jaybee18]

What happened:
The tests in a TestSuite fail, because the specified namespace does not exist.

What you expected to happen:
The TestSuite should create the namespace that is specified in the YAML, as it is described in the documentation:
https://kuttl.dev/docs/testing/reference.html#testsuite:~:text=%22kuttl%2Dtest%22-,namespace,-string

How to reproduce it (as minimally and precisely as possible):

# kuttl-test.yaml
apiVersion: kuttl.dev/v1beta1
kind: TestSuite
testDirs:
- ./mongodb
parallel: 1
namespace: "kuttl-tests-namespace"

# mongodb/01-install.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: demo
data:
  # property-like keys; each key maps to a simple value
  player_initial_lives: "3"
  ui_properties_file_name: "user-interface.properties"

  # file-like keys
  game.properties: |
    enemy.types=aliens,monsters
    player.maximum-lives=5    
  user-interface.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true  

And then run

kubectl kuttl test .

Anything else we need to know?:
The logs indicate that the namespace creation was purposefully skipped:

logger.go:42: 09:30:26 | mongodb | Skipping creation of user-supplied namespace: kuttl-tests-namespace

Environment:

• Kubernetes version (use kubectl version): v1.27.11-eks-b9c9ed7
• KUTTL version (use kubectl kuttl version):
  KUTTL Version: version.Info{GitVersion:"0.15.0", GitCommit:"f6d64c9", BuildDate:"2023-01-03T21:32:35Z", GoVersion:"go1.19.4", Compiler:"gc", Platform:"darwin/arm64"}
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others: